diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 66922b5..857ce3a 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -4,7 +4,8 @@ repos:
     hooks:
       - id: mypy
         args: [--strict]
-        additional_dependencies: [pydantic, pytest, pytest_mock]
+        additional_dependencies:
+          [pydantic, pytest, pytest_mock, types-requests, flagsmith-flag-engine, responses, types-pytz, sseclient-py]
   - repo: https://github.com/PyCQA/isort
     rev: 5.12.0
     hooks:
diff --git a/flagsmith/__init__.py b/flagsmith/__init__.py
index 46571d5..4fbd5fc 100644
--- a/flagsmith/__init__.py
+++ b/flagsmith/__init__.py
@@ -1 +1,3 @@
-from .flagsmith import Flagsmith  # noqa
+from .flagsmith import Flagsmith
+
+__all__ = ("Flagsmith",)
diff --git a/flagsmith/analytics.py b/flagsmith/analytics.py
index 97b596e..dee1ed5 100644
--- a/flagsmith/analytics.py
+++ b/flagsmith/analytics.py
@@ -1,12 +1,13 @@
 import json
+import typing
 from datetime import datetime
 
-from requests_futures.sessions import FuturesSession
+from requests_futures.sessions import FuturesSession  # type: ignore
 
-ANALYTICS_ENDPOINT = "analytics/flags/"
+ANALYTICS_ENDPOINT: typing.Final[str] = "analytics/flags/"
 
 # Used to control how often we send data(in seconds)
-ANALYTICS_TIMER = 10
+ANALYTICS_TIMER: typing.Final[int] = 10
 
 session = FuturesSession(max_workers=4)
 
@@ -17,7 +18,9 @@ class AnalyticsProcessor:
     the Flagsmith SDK. Docs: https://docs.flagsmith.com/advanced-use/flag-analytics.
     """
 
-    def __init__(self, environment_key: str, base_api_url: str, timeout: int = 3):
+    def __init__(
+        self, environment_key: str, base_api_url: str, timeout: typing.Optional[int] = 3
+    ):
         """
         Initialise the AnalyticsProcessor to handle sending analytics on flag usage to
         the Flagsmith API.
@@ -30,10 +33,10 @@ def __init__(self, environment_key: str, base_api_url: str, timeout: int = 3):
         self.analytics_endpoint = base_api_url + ANALYTICS_ENDPOINT
         self.environment_key = environment_key
         self._last_flushed = datetime.now()
-        self.analytics_data = {}
-        self.timeout = timeout
+        self.analytics_data: typing.MutableMapping[str, typing.Any] = {}
+        self.timeout = timeout or 3
 
-    def flush(self):
+    def flush(self) -> None:
         """
         Sends all the collected data to the api asynchronously and resets the timer
         """
@@ -53,7 +56,7 @@ def flush(self):
         self.analytics_data.clear()
         self._last_flushed = datetime.now()
 
-    def track_feature(self, feature_name: str):
+    def track_feature(self, feature_name: str) -> None:
         self.analytics_data[feature_name] = self.analytics_data.get(feature_name, 0) + 1
         if (datetime.now() - self._last_flushed).seconds > ANALYTICS_TIMER:
             self.flush()
diff --git a/flagsmith/flagsmith.py b/flagsmith/flagsmith.py
index a600182..3cd4c2b 100644
--- a/flagsmith/flagsmith.py
+++ b/flagsmith/flagsmith.py
@@ -20,13 +20,23 @@
 from flagsmith.offline_handlers import BaseOfflineHandler
 from flagsmith.polling_manager import EnvironmentDataPollingManager
 from flagsmith.streaming_manager import EventStreamManager, StreamEvent
-from flagsmith.utils.identities import generate_identities_data
+from flagsmith.utils.identities import Identity, generate_identities_data
 
 logger = logging.getLogger(__name__)
 
 DEFAULT_API_URL = "https://edge.api.flagsmith.com/api/v1/"
 DEFAULT_REALTIME_API_URL = "https://realtime.flagsmith.com/"
 
+JsonType = typing.Union[
+    None,
+    int,
+    str,
+    bool,
+    typing.List["JsonType"],
+    typing.List[typing.Mapping[str, "JsonType"]],
+    typing.Dict[str, "JsonType"],
+]
+
 
 class Flagsmith:
     """A Flagsmith client.
@@ -45,19 +55,21 @@ class Flagsmith:
 
     def __init__(
         self,
-        environment_key: str = None,
-        api_url: str = None,
+        environment_key: typing.Optional[str] = None,
+        api_url: typing.Optional[str] = None,
         realtime_api_url: typing.Optional[str] = None,
-        custom_headers: typing.Dict[str, typing.Any] = None,
-        request_timeout_seconds: int = None,
+        custom_headers: typing.Optional[typing.Dict[str, typing.Any]] = None,
+        request_timeout_seconds: typing.Optional[int] = None,
         enable_local_evaluation: bool = False,
         environment_refresh_interval_seconds: typing.Union[int, float] = 60,
-        retries: Retry = None,
+        retries: typing.Optional[Retry] = None,
         enable_analytics: bool = False,
-        default_flag_handler: typing.Callable[[str], DefaultFlag] = None,
-        proxies: typing.Dict[str, str] = None,
+        default_flag_handler: typing.Optional[
+            typing.Callable[[str], DefaultFlag]
+        ] = None,
+        proxies: typing.Optional[typing.Dict[str, str]] = None,
         offline_mode: bool = False,
-        offline_handler: BaseOfflineHandler = None,
+        offline_handler: typing.Optional[BaseOfflineHandler] = None,
         enable_realtime_updates: bool = False,
     ):
         """
@@ -94,8 +106,8 @@ def __init__(
         self.offline_handler = offline_handler
         self.default_flag_handler = default_flag_handler
         self.enable_realtime_updates = enable_realtime_updates
-        self._analytics_processor = None
-        self._environment = None
+        self._analytics_processor: typing.Optional[AnalyticsProcessor] = None
+        self._environment: typing.Optional[EnvironmentModel] = None
         self._identity_overrides_by_identifier: typing.Dict[str, IdentityModel] = {}
 
         # argument validation
@@ -159,6 +171,9 @@ def __init__(
     def _initialise_local_evaluation(self) -> None:
         if self.enable_realtime_updates:
             self.update_environment()
+            if not self._environment:
+                raise ValueError("Unable to get environment from API key")
+
             stream_url = f"{self.realtime_api_url}sse/environments/{self._environment.api_key}/stream"
 
             self.event_stream_thread = EventStreamManager(
@@ -196,6 +211,10 @@ def handle_stream_event(self, event: StreamEvent) -> None:
         if stream_updated_at.tzinfo is None:
             stream_updated_at = pytz.utc.localize(stream_updated_at)
 
+        if not self._environment:
+            raise ValueError(
+                "Unable to access environment. Environment should not be null"
+            )
         environment_updated_at = self._environment.updated_at
         if environment_updated_at.tzinfo is None:
             environment_updated_at = pytz.utc.localize(environment_updated_at)
@@ -214,7 +233,9 @@ def get_environment_flags(self) -> Flags:
         return self._get_environment_flags_from_api()
 
     def get_identity_flags(
-        self, identifier: str, traits: typing.Dict[str, typing.Any] = None
+        self,
+        identifier: str,
+        traits: typing.Optional[typing.Mapping[str, TraitValue]] = None,
     ) -> Flags:
         """
         Get all the flags for the current environment for a given identity. Will also
@@ -233,7 +254,9 @@ def get_identity_flags(
         return self._get_identity_flags_from_api(identifier, traits)
 
     def get_identity_segments(
-        self, identifier: str, traits: typing.Dict[str, typing.Any] = None
+        self,
+        identifier: str,
+        traits: typing.Optional[typing.Mapping[str, TraitValue]] = None,
     ) -> typing.List[Segment]:
         """
         Get a list of segments that the given identity is in.
@@ -255,7 +278,7 @@ def get_identity_segments(
         segment_models = get_identity_segments(self._environment, identity_model)
         return [Segment(id=sm.id, name=sm.name) for sm in segment_models]
 
-    def update_environment(self):
+    def update_environment(self) -> None:
         self._environment = self._get_environment_from_api()
         self._update_overrides()
 
@@ -272,6 +295,8 @@ def _get_environment_from_api(self) -> EnvironmentModel:
         return EnvironmentModel.model_validate(environment_data)
 
     def _get_environment_flags_from_document(self) -> Flags:
+        if self._environment is None:
+            raise TypeError("No environment present")
         return Flags.from_feature_state_models(
             feature_states=engine.get_environment_feature_states(self._environment),
             analytics_processor=self._analytics_processor,
@@ -279,9 +304,11 @@ def _get_environment_flags_from_document(self) -> Flags:
         )
 
     def _get_identity_flags_from_document(
-        self, identifier: str, traits: typing.Dict[str, typing.Any]
+        self, identifier: str, traits: typing.Mapping[str, TraitValue]
     ) -> Flags:
         identity_model = self._get_identity_model(identifier, **traits)
+        if self._environment is None:
+            raise TypeError("No environment present")
         feature_states = engine.get_identity_feature_states(
             self._environment, identity_model
         )
@@ -294,11 +321,11 @@ def _get_identity_flags_from_document(
 
     def _get_environment_flags_from_api(self) -> Flags:
         try:
-            api_flags = self._get_json_response(
-                url=self.environment_flags_url, method="GET"
-            )
+            json_response: typing.List[
+                typing.Mapping[str, JsonType]
+            ] = self._get_json_response(url=self.environment_flags_url, method="GET")
             return Flags.from_api_flags(
-                api_flags=api_flags,
+                api_flags=json_response,
                 analytics_processor=self._analytics_processor,
                 default_flag_handler=self.default_flag_handler,
             )
@@ -310,11 +337,13 @@ def _get_environment_flags_from_api(self) -> Flags:
             raise
 
     def _get_identity_flags_from_api(
-        self, identifier: str, traits: typing.Dict[str, typing.Any]
+        self, identifier: str, traits: typing.Mapping[str, typing.Any]
     ) -> Flags:
         try:
             data = generate_identities_data(identifier, traits)
-            json_response = self._get_json_response(
+            json_response: typing.Dict[
+                str, typing.List[typing.Dict[str, JsonType]]
+            ] = self._get_json_response(
                 url=self.identities_url, method="POST", body=data
             )
             return Flags.from_api_flags(
@@ -329,7 +358,14 @@ def _get_identity_flags_from_api(
                 return Flags(default_flag_handler=self.default_flag_handler)
             raise
 
-    def _get_json_response(self, url: str, method: str, body: dict = None):
+    def _get_json_response(
+        self,
+        url: str,
+        method: str,
+        body: typing.Optional[
+            typing.Union[Identity, typing.Dict[str, JsonType]]
+        ] = None,
+    ) -> typing.Any:
         try:
             request_method = getattr(self.session, method.lower())
             response = request_method(
@@ -371,7 +407,7 @@ def _get_identity_model(
             identity_traits=trait_models,
         )
 
-    def __del__(self):
+    def __del__(self) -> None:
         if hasattr(self, "environment_data_polling_manager_thread"):
             self.environment_data_polling_manager_thread.stop()
 
diff --git a/flagsmith/models.py b/flagsmith/models.py
index 41d0037..37bab3f 100644
--- a/flagsmith/models.py
+++ b/flagsmith/models.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import typing
 from dataclasses import dataclass, field
 
@@ -13,7 +15,7 @@ class BaseFlag:
     value: typing.Union[str, int, float, bool, None]
 
 
-@dataclass
+@dataclass()
 class DefaultFlag(BaseFlag):
     is_default: bool = field(default=True)
 
@@ -28,8 +30,8 @@ class Flag(BaseFlag):
     def from_feature_state_model(
         cls,
         feature_state_model: FeatureStateModel,
-        identity_id: typing.Union[str, int] = None,
-    ) -> "Flag":
+        identity_id: typing.Optional[typing.Union[str, int]] = None,
+    ) -> Flag:
         return Flag(
             enabled=feature_state_model.enabled,
             value=feature_state_model.get_value(identity_id=identity_id),
@@ -38,7 +40,7 @@ def from_feature_state_model(
         )
 
     @classmethod
-    def from_api_flag(cls, flag_data: dict) -> "Flag":
+    def from_api_flag(cls, flag_data: typing.Mapping[str, typing.Any]) -> Flag:
         return Flag(
             enabled=flag_data["enabled"],
             value=flag_data["feature_state_value"],
@@ -50,17 +52,17 @@ def from_api_flag(cls, flag_data: dict) -> "Flag":
 @dataclass
 class Flags:
     flags: typing.Dict[str, Flag] = field(default_factory=dict)
-    default_flag_handler: typing.Callable[[str], DefaultFlag] = None
-    _analytics_processor: AnalyticsProcessor = None
+    default_flag_handler: typing.Optional[typing.Callable[[str], DefaultFlag]] = None
+    _analytics_processor: typing.Optional[AnalyticsProcessor] = None
 
     @classmethod
     def from_feature_state_models(
         cls,
-        feature_states: typing.List[FeatureStateModel],
-        analytics_processor: AnalyticsProcessor,
-        default_flag_handler: typing.Callable,
-        identity_id: typing.Union[str, int] = None,
-    ) -> "Flags":
+        feature_states: typing.Sequence[FeatureStateModel],
+        analytics_processor: typing.Optional[AnalyticsProcessor],
+        default_flag_handler: typing.Optional[typing.Callable[[str], DefaultFlag]],
+        identity_id: typing.Optional[typing.Union[str, int]] = None,
+    ) -> Flags:
         flags = {
             feature_state.feature.name: Flag.from_feature_state_model(
                 feature_state, identity_id=identity_id
@@ -77,10 +79,10 @@ def from_feature_state_models(
     @classmethod
     def from_api_flags(
         cls,
-        api_flags: typing.List[dict],
-        analytics_processor: AnalyticsProcessor,
-        default_flag_handler: typing.Callable,
-    ) -> "Flags":
+        api_flags: typing.Sequence[typing.Mapping[str, typing.Any]],
+        analytics_processor: typing.Optional[AnalyticsProcessor],
+        default_flag_handler: typing.Optional[typing.Callable[[str], DefaultFlag]],
+    ) -> Flags:
         flags = {
             flag_data["feature"]["name"]: Flag.from_api_flag(flag_data)
             for flag_data in api_flags
@@ -120,12 +122,12 @@ def get_feature_value(self, feature_name: str) -> typing.Any:
         """
         return self.get_flag(feature_name).value
 
-    def get_flag(self, feature_name: str) -> BaseFlag:
+    def get_flag(self, feature_name: str) -> typing.Union[DefaultFlag, Flag]:
         """
         Get a specific flag given the feature name.
 
         :param feature_name: the name of the feature to retrieve the flag for.
-        :return: BaseFlag object.
+        :return: DefaultFlag | Flag object.
         :raises FlagsmithClientError: if feature doesn't exist
         """
         try:
diff --git a/flagsmith/polling_manager.py b/flagsmith/polling_manager.py
index e922ea8..85b8486 100644
--- a/flagsmith/polling_manager.py
+++ b/flagsmith/polling_manager.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import logging
 import threading
 import time
@@ -16,10 +18,10 @@
 class EnvironmentDataPollingManager(threading.Thread):
     def __init__(
         self,
-        *args,
-        main: "Flagsmith",
+        *args: typing.Any,
+        main: Flagsmith,
         refresh_interval_seconds: typing.Union[int, float] = 10,
-        **kwargs
+        **kwargs: typing.Any,
     ):
         super(EnvironmentDataPollingManager, self).__init__(*args, **kwargs)
         self._stop_event = threading.Event()
@@ -37,5 +39,5 @@ def run(self) -> None:
     def stop(self) -> None:
         self._stop_event.set()
 
-    def __del__(self):
+    def __del__(self) -> None:
         self._stop_event.set()
diff --git a/flagsmith/streaming_manager.py b/flagsmith/streaming_manager.py
index 64ac6a7..3fc6817 100644
--- a/flagsmith/streaming_manager.py
+++ b/flagsmith/streaming_manager.py
@@ -1,5 +1,6 @@
 import logging
 import threading
+import typing
 from typing import Callable, Generator, Optional, Protocol, cast
 
 import requests
@@ -17,11 +18,11 @@ class StreamEvent(Protocol):
 class EventStreamManager(threading.Thread):
     def __init__(
         self,
-        *args,
+        *args: typing.Any,
         stream_url: str,
         on_event: Callable[[StreamEvent], None],
         request_timeout_seconds: Optional[int] = None,
-        **kwargs
+        **kwargs: typing.Any
     ) -> None:
         super().__init__(*args, **kwargs)
         self._stop_event = threading.Event()
diff --git a/flagsmith/utils/identities.py b/flagsmith/utils/identities.py
index 9c82333..79d8875 100644
--- a/flagsmith/utils/identities.py
+++ b/flagsmith/utils/identities.py
@@ -1,5 +1,19 @@
-def generate_identities_data(identifier: str, traits: dict = None):
+import typing
+
+from flag_engine.identities.traits.types import TraitValue
+
+Identity = typing.TypedDict(
+    "Identity",
+    {"identifier": str, "traits": typing.List[typing.Mapping[str, TraitValue]]},
+)
+
+
+def generate_identities_data(
+    identifier: str, traits: typing.Optional[typing.Mapping[str, TraitValue]] = None
+) -> Identity:
     return {
         "identifier": identifier,
-        "traits": [{"trait_key": k, "trait_value": v} for k, v in traits.items()],
+        "traits": [{"trait_key": k, "trait_value": v} for k, v in traits.items()]
+        if traits
+        else [],
     }
diff --git a/poetry.lock b/poetry.lock
index 587401e..c8990ce 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -206,6 +206,73 @@ files = [
     {file = "colorama-0.4.6.tar.gz", hash = "sha256:08695f5cb7ed6e0531a20572697297273c47b8cae5a63ffc6d6ed5c201be6e44"},
 ]
 
+[[package]]
+name = "coverage"
+version = "7.4.3"
+description = "Code coverage measurement for Python"
+optional = false
+python-versions = ">=3.8"
+files = [
+    {file = "coverage-7.4.3-cp310-cp310-macosx_10_9_x86_64.whl", hash = "sha256:8580b827d4746d47294c0e0b92854c85a92c2227927433998f0d3320ae8a71b6"},
+    {file = "coverage-7.4.3-cp310-cp310-macosx_11_0_arm64.whl", hash = "sha256:718187eeb9849fc6cc23e0d9b092bc2348821c5e1a901c9f8975df0bc785bfd4"},
+    {file = "coverage-7.4.3-cp310-cp310-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:767b35c3a246bcb55b8044fd3a43b8cd553dd1f9f2c1eeb87a302b1f8daa0524"},
+    {file = "coverage-7.4.3-cp310-cp310-manylinux_2_5_i686.manylinux1_i686.manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:ae7f19afe0cce50039e2c782bff379c7e347cba335429678450b8fe81c4ef96d"},
+    {file = "coverage-7.4.3-cp310-cp310-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:ba3a8aaed13770e970b3df46980cb068d1c24af1a1968b7818b69af8c4347efb"},
+    {file = "coverage-7.4.3-cp310-cp310-musllinux_1_1_aarch64.whl", hash = "sha256:ee866acc0861caebb4f2ab79f0b94dbfbdbfadc19f82e6e9c93930f74e11d7a0"},
+    {file = "coverage-7.4.3-cp310-cp310-musllinux_1_1_i686.whl", hash = "sha256:506edb1dd49e13a2d4cac6a5173317b82a23c9d6e8df63efb4f0380de0fbccbc"},
+    {file = "coverage-7.4.3-cp310-cp310-musllinux_1_1_x86_64.whl", hash = "sha256:fd6545d97c98a192c5ac995d21c894b581f1fd14cf389be90724d21808b657e2"},
+    {file = "coverage-7.4.3-cp310-cp310-win32.whl", hash = "sha256:f6a09b360d67e589236a44f0c39218a8efba2593b6abdccc300a8862cffc2f94"},
+    {file = "coverage-7.4.3-cp310-cp310-win_amd64.whl", hash = "sha256:18d90523ce7553dd0b7e23cbb28865db23cddfd683a38fb224115f7826de78d0"},
+    {file = "coverage-7.4.3-cp311-cp311-macosx_10_9_x86_64.whl", hash = "sha256:cbbe5e739d45a52f3200a771c6d2c7acf89eb2524890a4a3aa1a7fa0695d2a47"},
+    {file = "coverage-7.4.3-cp311-cp311-macosx_11_0_arm64.whl", hash = "sha256:489763b2d037b164846ebac0cbd368b8a4ca56385c4090807ff9fad817de4113"},
+    {file = "coverage-7.4.3-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:451f433ad901b3bb00184d83fd83d135fb682d780b38af7944c9faeecb1e0bfe"},
+    {file = "coverage-7.4.3-cp311-cp311-manylinux_2_5_i686.manylinux1_i686.manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:fcc66e222cf4c719fe7722a403888b1f5e1682d1679bd780e2b26c18bb648cdc"},
+    {file = "coverage-7.4.3-cp311-cp311-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:b3ec74cfef2d985e145baae90d9b1b32f85e1741b04cd967aaf9cfa84c1334f3"},
+    {file = "coverage-7.4.3-cp311-cp311-musllinux_1_1_aarch64.whl", hash = "sha256:abbbd8093c5229c72d4c2926afaee0e6e3140de69d5dcd918b2921f2f0c8baba"},
+    {file = "coverage-7.4.3-cp311-cp311-musllinux_1_1_i686.whl", hash = "sha256:35eb581efdacf7b7422af677b92170da4ef34500467381e805944a3201df2079"},
+    {file = "coverage-7.4.3-cp311-cp311-musllinux_1_1_x86_64.whl", hash = "sha256:8249b1c7334be8f8c3abcaaa996e1e4927b0e5a23b65f5bf6cfe3180d8ca7840"},
+    {file = "coverage-7.4.3-cp311-cp311-win32.whl", hash = "sha256:cf30900aa1ba595312ae41978b95e256e419d8a823af79ce670835409fc02ad3"},
+    {file = "coverage-7.4.3-cp311-cp311-win_amd64.whl", hash = "sha256:18c7320695c949de11a351742ee001849912fd57e62a706d83dfc1581897fa2e"},
+    {file = "coverage-7.4.3-cp312-cp312-macosx_10_9_x86_64.whl", hash = "sha256:b51bfc348925e92a9bd9b2e48dad13431b57011fd1038f08316e6bf1df107d10"},
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+    {file = "coverage-7.4.3-cp39-cp39-manylinux_2_5_i686.manylinux1_i686.manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:4af154d617c875b52651dd8dd17a31270c495082f3d55f6128e7629658d63765"},
+    {file = "coverage-7.4.3-cp39-cp39-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:8640f1fde5e1b8e3439fe482cdc2b0bb6c329f4bb161927c28d2e8879c6029ee"},
+    {file = "coverage-7.4.3-cp39-cp39-musllinux_1_1_aarch64.whl", hash = "sha256:69b9f6f66c0af29642e73a520b6fed25ff9fd69a25975ebe6acb297234eda501"},
+    {file = "coverage-7.4.3-cp39-cp39-musllinux_1_1_i686.whl", hash = "sha256:0842571634f39016a6c03e9d4aba502be652a6e4455fadb73cd3a3a49173e38f"},
+    {file = "coverage-7.4.3-cp39-cp39-musllinux_1_1_x86_64.whl", hash = "sha256:a78ed23b08e8ab524551f52953a8a05d61c3a760781762aac49f8de6eede8c45"},
+    {file = "coverage-7.4.3-cp39-cp39-win32.whl", hash = "sha256:c0524de3ff096e15fcbfe8f056fdb4ea0bf497d584454f344d59fce069d3e6e9"},
+    {file = "coverage-7.4.3-cp39-cp39-win_amd64.whl", hash = "sha256:0209a6369ccce576b43bb227dc8322d8ef9e323d089c6f3f26a597b09cb4d2aa"},
+    {file = "coverage-7.4.3-pp38.pp39.pp310-none-any.whl", hash = "sha256:7cbde573904625509a3f37b6fecea974e363460b556a627c60dc2f47e2fffa51"},
+    {file = "coverage-7.4.3.tar.gz", hash = "sha256:276f6077a5c61447a48d133ed13e759c09e62aff0dc84274a68dc18660104d52"},
+]
+
+[package.dependencies]
+tomli = {version = "*", optional = true, markers = "python_full_version <= \"3.11.0a6\" and extra == \"toml\""}
+
+[package.extras]
+toml = ["tomli"]
+
 [[package]]
 name = "distlib"
 version = "0.3.8"
@@ -494,13 +561,13 @@ files = [
 
 [[package]]
 name = "pydantic"
-version = "2.6.4"
+version = "2.6.3"
 description = "Data validation using Python type hints"
 optional = false
 python-versions = ">=3.8"
 files = [
-    {file = "pydantic-2.6.4-py3-none-any.whl", hash = "sha256:cc46fce86607580867bdc3361ad462bab9c222ef042d3da86f2fb333e1d916c5"},
-    {file = "pydantic-2.6.4.tar.gz", hash = "sha256:b1704e0847db01817624a6b86766967f552dd9dbf3afba4004409f908dcc84e6"},
+    {file = "pydantic-2.6.3-py3-none-any.whl", hash = "sha256:72c6034df47f46ccdf81869fddb81aade68056003900a8724a4f160700016a2a"},
+    {file = "pydantic-2.6.3.tar.gz", hash = "sha256:e07805c4c7f5c6826e33a1d4c9d47950d7eaf34868e2690f8594d2e30241f11f"},
 ]
 
 [package.dependencies]
@@ -650,6 +717,24 @@ tomli = {version = ">=1.0.0", markers = "python_version < \"3.11\""}
 [package.extras]
 testing = ["argcomplete", "attrs (>=19.2.0)", "hypothesis (>=3.56)", "mock", "nose", "pygments (>=2.7.2)", "requests", "setuptools", "xmlschema"]
 
+[[package]]
+name = "pytest-cov"
+version = "4.1.0"
+description = "Pytest plugin for measuring coverage."
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "pytest-cov-4.1.0.tar.gz", hash = "sha256:3904b13dfbfec47f003b8e77fd5b589cd11904a21ddf1ab38a64f204d6a10ef6"},
+    {file = "pytest_cov-4.1.0-py3-none-any.whl", hash = "sha256:6ba70b9e97e69fcc3fb45bfeab2d0a138fb65c4d0d6a41ef33983ad114be8c3a"},
+]
+
+[package.dependencies]
+coverage = {version = ">=5.2.1", extras = ["toml"]}
+pytest = ">=4.6"
+
+[package.extras]
+testing = ["fields", "hunter", "process-tests", "pytest-xdist", "six", "virtualenv"]
+
 [[package]]
 name = "pytest-mock"
 version = "3.12.0"
@@ -777,22 +862,22 @@ dev = ["black (>=22.3.0)", "build (>=0.7.0)", "isort (>=5.11.4)", "pyflakes (>=2
 
 [[package]]
 name = "responses"
-version = "0.17.0"
+version = "0.24.1"
 description = "A utility library for mocking out the `requests` Python library."
 optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
+python-versions = ">=3.8"
 files = [
-    {file = "responses-0.17.0-py2.py3-none-any.whl", hash = "sha256:e4fc472fb7374fb8f84fcefa51c515ca4351f198852b4eb7fc88223780b472ea"},
-    {file = "responses-0.17.0.tar.gz", hash = "sha256:ec675e080d06bf8d1fb5e5a68a1e5cd0df46b09c78230315f650af5e4036bec7"},
+    {file = "responses-0.24.1-py3-none-any.whl", hash = "sha256:a2b43f4c08bfb9c9bd242568328c65a34b318741d3fab884ac843c5ceeb543f9"},
+    {file = "responses-0.24.1.tar.gz", hash = "sha256:b127c6ca3f8df0eb9cc82fd93109a3007a86acb24871834c47b77765152ecf8c"},
 ]
 
 [package.dependencies]
-requests = ">=2.0"
-six = "*"
-urllib3 = ">=1.25.10"
+pyyaml = "*"
+requests = ">=2.30.0,<3.0"
+urllib3 = ">=1.25.10,<3.0"
 
 [package.extras]
-tests = ["coverage (>=3.7.1,<6.0.0)", "flake8", "mypy", "pytest (>=4.6)", "pytest (>=4.6,<5.0)", "pytest-cov", "pytest-localserver", "types-mock", "types-requests", "types-six"]
+tests = ["coverage (>=6.0.0)", "flake8", "mypy", "pytest (>=7.0.0)", "pytest-asyncio", "pytest-cov", "pytest-httpserver", "tomli", "tomli-w", "types-PyYAML", "types-requests"]
 
 [[package]]
 name = "semver"
@@ -821,17 +906,6 @@ docs = ["furo", "jaraco.packaging (>=9.3)", "jaraco.tidelift (>=1.4)", "pygments
 testing = ["build[virtualenv]", "filelock (>=3.4.0)", "flake8-2020", "ini2toml[lite] (>=0.9)", "jaraco.develop (>=7.21)", "jaraco.envs (>=2.2)", "jaraco.path (>=3.2.0)", "packaging (>=23.2)", "pip (>=19.1)", "pytest (>=6)", "pytest-checkdocs (>=2.4)", "pytest-cov", "pytest-enabler (>=2.2)", "pytest-home (>=0.5)", "pytest-mypy (>=0.9.1)", "pytest-perf", "pytest-ruff (>=0.2.1)", "pytest-timeout", "pytest-xdist", "tomli-w (>=1.0.0)", "virtualenv (>=13.0.0)", "wheel"]
 testing-integration = ["build[virtualenv] (>=1.0.3)", "filelock (>=3.4.0)", "jaraco.envs (>=2.2)", "jaraco.path (>=3.2.0)", "packaging (>=23.2)", "pytest", "pytest-enabler", "pytest-xdist", "tomli", "virtualenv (>=13.0.0)", "wheel"]
 
-[[package]]
-name = "six"
-version = "1.16.0"
-description = "Python 2 and 3 compatibility utilities"
-optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*"
-files = [
-    {file = "six-1.16.0-py2.py3-none-any.whl", hash = "sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254"},
-    {file = "six-1.16.0.tar.gz", hash = "sha256:1e61c37477a1626458e36f7b1d82aa5c9b094fa4802892072e49de9c60c4c926"},
-]
-
 [[package]]
 name = "sseclient-py"
 version = "1.8.0"
@@ -854,6 +928,31 @@ files = [
     {file = "tomli-2.0.1.tar.gz", hash = "sha256:de526c12914f0c550d15924c62d72abc48d6fe7364aa87328337a31007fe8a4f"},
 ]
 
+[[package]]
+name = "types-pytz"
+version = "2024.1.0.20240203"
+description = "Typing stubs for pytz"
+optional = false
+python-versions = ">=3.8"
+files = [
+    {file = "types-pytz-2024.1.0.20240203.tar.gz", hash = "sha256:c93751ee20dfc6e054a0148f8f5227b9a00b79c90a4d3c9f464711a73179c89e"},
+    {file = "types_pytz-2024.1.0.20240203-py3-none-any.whl", hash = "sha256:9679eef0365db3af91ef7722c199dbb75ee5c1b67e3c4dd7bfbeb1b8a71c21a3"},
+]
+
+[[package]]
+name = "types-requests"
+version = "2.31.0.20240218"
+description = "Typing stubs for requests"
+optional = false
+python-versions = ">=3.8"
+files = [
+    {file = "types-requests-2.31.0.20240218.tar.gz", hash = "sha256:f1721dba8385958f504a5386240b92de4734e047a08a40751c1654d1ac3349c5"},
+    {file = "types_requests-2.31.0.20240218-py3-none-any.whl", hash = "sha256:a82807ec6ddce8f00fe0e949da6d6bc1fbf1715420218a9640d695f70a9e5a9b"},
+]
+
+[package.dependencies]
+urllib3 = ">=2"
+
 [[package]]
 name = "typing-extensions"
 version = "4.10.0"
@@ -905,4 +1004,4 @@ test = ["covdefaults (>=2.3)", "coverage (>=7.2.7)", "coverage-enable-subprocess
 [metadata]
 lock-version = "2.0"
 python-versions = ">=3.8.1,<4"
-content-hash = "17bb40bb6fbdd32e257c5503306d4d040b531fd1670c8fcfbafede74fdc9d4a5"
+content-hash = "98662db30ac17a633b8b5a92816f464847c1c48d68f57842863af90444605b25"
diff --git a/pyproject.toml b/pyproject.toml
index b862f07..a6558c8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,13 +25,18 @@ pytest = "^7.4.0"
 pytest-mock = "^3.6.1"
 black = "^23.3.0"
 pre-commit = "^2.17.0"
-responses = "^0.17.0"
+responses = "^0.24.1"
 flake8 = "^6.1.0"
 isort = "^5.12.0"
 mypy = "^1.7.1"
+types-requests = "^2.31.0.10"
+pytest-cov = "^4.1.0"
+types-pytz = "^2024.1.0.20240203"
 
 [tool.mypy]
 plugins = ["pydantic.mypy"]
+exclude = ["example/*"]
+
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]
diff --git a/tests/conftest.py b/tests/conftest.py
index d13c761..0d28bf2 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -2,6 +2,7 @@
 import os
 import random
 import string
+import typing
 from typing import Generator
 
 import pytest
@@ -16,37 +17,35 @@
 
 
 @pytest.fixture()
-def analytics_processor():
+def analytics_processor() -> AnalyticsProcessor:
     return AnalyticsProcessor(
         environment_key="test_key", base_api_url="http://test_url"
     )
 
 
 @pytest.fixture(scope="session")
-def api_key():
+def api_key() -> str:
     return "".join(random.sample(string.ascii_letters, 20))
 
 
 @pytest.fixture(scope="session")
-def server_api_key():
+def server_api_key() -> str:
     return "ser.%s" % "".join(random.sample(string.ascii_letters, 20))
 
 
 @pytest.fixture()
-def flagsmith(api_key):
+def flagsmith(api_key: str) -> Flagsmith:
     return Flagsmith(environment_key=api_key)
 
 
 @pytest.fixture()
-def environment_json():
+def environment_json() -> typing.Generator[str, None, None]:
     with open(os.path.join(DATA_DIR, "environment.json"), "rt") as f:
         yield f.read()
 
 
 @pytest.fixture()
-def requests_session_response_ok(
-    mocker: Generator[MockerFixture, None, None], environment_json: str
-) -> None:
+def requests_session_response_ok(mocker: MockerFixture, environment_json: str) -> None:
     mock_session = mocker.MagicMock()
     mocker.patch("flagsmith.flagsmith.requests.Session", return_value=mock_session)
 
@@ -76,13 +75,13 @@ def environment_model(environment_json: str) -> EnvironmentModel:
 
 
 @pytest.fixture()
-def flags_json():
+def flags_json() -> typing.Generator[str, None, None]:
     with open(os.path.join(DATA_DIR, "flags.json"), "rt") as f:
         yield f.read()
 
 
 @pytest.fixture()
-def identities_json():
+def identities_json() -> typing.Generator[str, None, None]:
     with open(os.path.join(DATA_DIR, "identities.json"), "rt") as f:
         yield f.read()
 
diff --git a/tests/test_analytics.py b/tests/test_analytics.py
index 60126b4..7a2fd65 100644
--- a/tests/test_analytics.py
+++ b/tests/test_analytics.py
@@ -2,10 +2,12 @@
 from datetime import datetime, timedelta
 from unittest import mock
 
-from flagsmith.analytics import ANALYTICS_TIMER
+from flagsmith.analytics import ANALYTICS_TIMER, AnalyticsProcessor
 
 
-def test_analytics_processor_track_feature_updates_analytics_data(analytics_processor):
+def test_analytics_processor_track_feature_updates_analytics_data(
+    analytics_processor: AnalyticsProcessor,
+) -> None:
     # When
     analytics_processor.track_feature("my_feature")
     assert analytics_processor.analytics_data["my_feature"] == 1
@@ -14,15 +16,17 @@ def test_analytics_processor_track_feature_updates_analytics_data(analytics_proc
     assert analytics_processor.analytics_data["my_feature"] == 2
 
 
-def test_analytics_processor_flush_clears_analytics_data(analytics_processor):
+def test_analytics_processor_flush_clears_analytics_data(
+    analytics_processor: AnalyticsProcessor,
+) -> None:
     analytics_processor.track_feature("my_feature")
     analytics_processor.flush()
     assert analytics_processor.analytics_data == {}
 
 
 def test_analytics_processor_flush_post_request_data_match_ananlytics_data(
-    analytics_processor,
-):
+    analytics_processor: AnalyticsProcessor,
+) -> None:
     # Given
     with mock.patch("flagsmith.analytics.session") as session:
         # When
@@ -36,8 +40,8 @@ def test_analytics_processor_flush_post_request_data_match_ananlytics_data(
 
 
 def test_analytics_processor_flush_early_exit_if_analytics_data_is_empty(
-    analytics_processor,
-):
+    analytics_processor: AnalyticsProcessor,
+) -> None:
     with mock.patch("flagsmith.analytics.session") as session:
         analytics_processor.flush()
 
@@ -46,8 +50,8 @@ def test_analytics_processor_flush_early_exit_if_analytics_data_is_empty(
 
 
 def test_analytics_processor_calling_track_feature_calls_flush_when_timer_runs_out(
-    analytics_processor,
-):
+    analytics_processor: AnalyticsProcessor,
+) -> None:
     # Given
     with mock.patch("flagsmith.analytics.datetime") as mocked_datetime, mock.patch(
         "flagsmith.analytics.session"
diff --git a/tests/test_flagsmith.py b/tests/test_flagsmith.py
index 9d0d23c..f6afdbc 100644
--- a/tests/test_flagsmith.py
+++ b/tests/test_flagsmith.py
@@ -6,19 +6,19 @@
 import pytest
 import requests
 import responses
+from flag_engine.environments.models import EnvironmentModel
 from flag_engine.features.models import FeatureModel, FeatureStateModel
+from pytest_mock import MockerFixture
 
 from flagsmith import Flagsmith
 from flagsmith.exceptions import FlagsmithAPIError
 from flagsmith.models import DefaultFlag, Flags
 from flagsmith.offline_handlers import BaseOfflineHandler
 
-if typing.TYPE_CHECKING:
-    from flag_engine.environments.models import EnvironmentModel
-    from pytest_mock import MockerFixture
 
-
-def test_flagsmith_starts_polling_manager_on_init_if_enabled(mocker, server_api_key):
+def test_flagsmith_starts_polling_manager_on_init_if_enabled(
+    mocker: MockerFixture, server_api_key: str
+) -> None:
     # Given
     mock_polling_manager = mocker.MagicMock()
     mocker.patch(
@@ -35,8 +35,8 @@ def test_flagsmith_starts_polling_manager_on_init_if_enabled(mocker, server_api_
 
 @responses.activate()
 def test_update_environment_sets_environment(
-    flagsmith, environment_json, environment_model
-):
+    flagsmith: Flagsmith, environment_json: str, environment_model: EnvironmentModel
+) -> None:
     # Given
     responses.add(method="GET", url=flagsmith.environment_url, body=environment_json)
     assert flagsmith._environment is None
@@ -51,8 +51,8 @@ def test_update_environment_sets_environment(
 
 @responses.activate()
 def test_get_environment_flags_calls_api_when_no_local_environment(
-    api_key, flagsmith, flags_json
-):
+    api_key: str, flagsmith: Flagsmith, flags_json: str
+) -> None:
     # Given
     responses.add(method="GET", url=flagsmith.environment_flags_url, body=flags_json)
 
@@ -71,8 +71,8 @@ def test_get_environment_flags_calls_api_when_no_local_environment(
 
 @responses.activate()
 def test_get_environment_flags_uses_local_environment_when_available(
-    flagsmith, environment_model
-):
+    flagsmith: Flagsmith, environment_model: EnvironmentModel
+) -> None:
     # Given
     flagsmith._environment = environment_model
     flagsmith.enable_local_evaluation = True
@@ -90,8 +90,8 @@ def test_get_environment_flags_uses_local_environment_when_available(
 
 @responses.activate()
 def test_get_identity_flags_calls_api_when_no_local_environment_no_traits(
-    flagsmith, identities_json
-):
+    flagsmith: Flagsmith, identities_json: str
+) -> None:
     # Given
     responses.add(method="POST", url=flagsmith.identities_url, body=identities_json)
     identifier = "identifier"
@@ -100,9 +100,11 @@ def test_get_identity_flags_calls_api_when_no_local_environment_no_traits(
     identity_flags = flagsmith.get_identity_flags(identifier=identifier).all_flags()
 
     # Then
-    assert responses.calls[0].request.body.decode() == json.dumps(
-        {"identifier": identifier, "traits": []}
-    )
+    body = responses.calls[0].request.body
+    if isinstance(body, bytes):
+        # Decode 'body' from bytes to string if it is in bytes format.
+        body = body.decode()
+    assert body == json.dumps({"identifier": identifier, "traits": []})
 
     # Taken from hard coded values in tests/data/identities.json
     assert identity_flags[0].enabled is True
@@ -112,8 +114,8 @@ def test_get_identity_flags_calls_api_when_no_local_environment_no_traits(
 
 @responses.activate()
 def test_get_identity_flags_calls_api_when_no_local_environment_with_traits(
-    flagsmith, identities_json
-):
+    flagsmith: Flagsmith, identities_json: str
+) -> None:
     # Given
     responses.add(method="POST", url=flagsmith.identities_url, body=identities_json)
     identifier = "identifier"
@@ -123,7 +125,11 @@ def test_get_identity_flags_calls_api_when_no_local_environment_with_traits(
     identity_flags = flagsmith.get_identity_flags(identifier=identifier, traits=traits)
 
     # Then
-    assert responses.calls[0].request.body.decode() == json.dumps(
+    body = responses.calls[0].request.body
+    if isinstance(body, bytes):
+        # Decode 'body' from bytes to string if it is in bytes format.
+        body = body.decode()
+    assert body == json.dumps(
         {
             "identifier": identifier,
             "traits": [{"trait_key": k, "trait_value": v} for k, v in traits.items()],
@@ -138,8 +144,8 @@ def test_get_identity_flags_calls_api_when_no_local_environment_with_traits(
 
 @responses.activate()
 def test_get_identity_flags_uses_local_environment_when_available(
-    flagsmith, environment_model, mocker
-):
+    flagsmith: Flagsmith, environment_model: EnvironmentModel, mocker: MockerFixture
+) -> None:
     # Given
     flagsmith._environment = environment_model
     flagsmith.enable_local_evaluation = True
@@ -163,7 +169,9 @@ def test_get_identity_flags_uses_local_environment_when_available(
     assert identity_flags[0].value == feature_state.get_value()
 
 
-def test_request_connection_error_raises_flagsmith_api_error(mocker, api_key):
+def test_request_connection_error_raises_flagsmith_api_error(
+    mocker: MockerFixture, api_key: str
+) -> None:
     """
     Test the behaviour when session.<method> raises a ConnectionError. Note that this
     does not account for the fact that we are using retries. Since this is a standard
@@ -188,7 +196,7 @@ def test_request_connection_error_raises_flagsmith_api_error(mocker, api_key):
 
 
 @responses.activate()
-def test_non_200_response_raises_flagsmith_api_error(flagsmith):
+def test_non_200_response_raises_flagsmith_api_error(flagsmith: Flagsmith) -> None:
     # Given
     responses.add(url=flagsmith.environment_flags_url, method="GET", status=400)
 
@@ -201,7 +209,7 @@ def test_non_200_response_raises_flagsmith_api_error(flagsmith):
 
 
 @responses.activate()
-def test_default_flag_is_used_when_no_environment_flags_returned(api_key):
+def test_default_flag_is_used_when_no_environment_flags_returned(api_key: str) -> None:
     # Given
     feature_name = "some_feature"
 
@@ -232,7 +240,9 @@ def default_flag_handler(feature_name: str) -> DefaultFlag:
 
 
 @responses.activate()
-def test_default_flag_is_not_used_when_environment_flags_returned(api_key, flags_json):
+def test_default_flag_is_not_used_when_environment_flags_returned(
+    api_key: str, flags_json: str
+) -> None:
     # Given
     feature_name = "some_feature"
 
@@ -261,7 +271,7 @@ def default_flag_handler(feature_name: str) -> DefaultFlag:
 
 
 @responses.activate()
-def test_default_flag_is_used_when_no_identity_flags_returned(api_key):
+def test_default_flag_is_used_when_no_identity_flags_returned(api_key: str) -> None:
     # Given
     feature_name = "some_feature"
 
@@ -276,7 +286,10 @@ def default_flag_handler(feature_name: str) -> DefaultFlag:
     )
 
     # and we mock the API to return an empty list of flags
-    response_data = {"flags": [], "traits": []}
+    response_data: typing.Mapping[str, typing.Sequence[typing.Any]] = {
+        "flags": [],
+        "traits": [],
+    }
     responses.add(
         url=flagsmith.identities_url, method="POST", body=json.dumps(response_data)
     )
@@ -294,8 +307,8 @@ def default_flag_handler(feature_name: str) -> DefaultFlag:
 
 @responses.activate()
 def test_default_flag_is_not_used_when_identity_flags_returned(
-    api_key, identities_json
-):
+    api_key: str, identities_json: str
+) -> None:
     # Given
     feature_name = "some_feature"
 
@@ -323,7 +336,9 @@ def default_flag_handler(feature_name: str) -> DefaultFlag:
     assert flag.value == "some-value"  # hard coded value in tests/data/identities.json
 
 
-def test_default_flags_are_used_if_api_error_and_default_flag_handler_given(mocker):
+def test_default_flags_are_used_if_api_error_and_default_flag_handler_given(
+    mocker: MockerFixture,
+) -> None:
     # Given
     # a default flag and associated handler
     default_flag = DefaultFlag(True, "some-default-value")
@@ -347,7 +362,9 @@ def default_flag_handler(feature_name: str) -> DefaultFlag:
     assert flags.get_flag("some-feature") == default_flag
 
 
-def test_get_identity_segments_no_traits(local_eval_flagsmith, environment_model):
+def test_get_identity_segments_no_traits(
+    local_eval_flagsmith: Flagsmith, environment_model: EnvironmentModel
+) -> None:
     # Given
     identifier = "identifier"
 
@@ -359,8 +376,8 @@ def test_get_identity_segments_no_traits(local_eval_flagsmith, environment_model
 
 
 def test_get_identity_segments_with_valid_trait(
-    local_eval_flagsmith, environment_model
-):
+    local_eval_flagsmith: Flagsmith, environment_model: EnvironmentModel
+) -> None:
     # Given
     identifier = "identifier"
     traits = {"foo": "bar"}  # obtained from data/environment.json
@@ -373,12 +390,12 @@ def test_get_identity_segments_with_valid_trait(
     assert segments[0].name == "Test segment"  # obtained from data/environment.json
 
 
-def test_local_evaluation_requires_server_key():
+def test_local_evaluation_requires_server_key() -> None:
     with pytest.raises(ValueError):
         Flagsmith(environment_key="not-a-server-key", enable_local_evaluation=True)
 
 
-def test_initialise_flagsmith_with_proxies():
+def test_initialise_flagsmith_with_proxies() -> None:
     # Given
     proxies = {"https": "https://my.proxy.com/proxy-me"}
 
@@ -389,10 +406,10 @@ def test_initialise_flagsmith_with_proxies():
     assert flagsmith.session.proxies == proxies
 
 
-def test_offline_mode(environment_model: "EnvironmentModel") -> None:
+def test_offline_mode(environment_model: EnvironmentModel) -> None:
     # Given
     class DummyOfflineHandler(BaseOfflineHandler):
-        def get_environment(self) -> "EnvironmentModel":
+        def get_environment(self) -> EnvironmentModel:
             return environment_model
 
     # When
@@ -409,7 +426,7 @@ def get_environment(self) -> "EnvironmentModel":
 
 @responses.activate()
 def test_flagsmith_uses_offline_handler_if_set_and_no_api_response(
-    mocker: "MockerFixture", environment_model: "EnvironmentModel"
+    mocker: MockerFixture, environment_model: EnvironmentModel
 ) -> None:
     # Given
     api_url = "http://some.flagsmith.com/api/v1/"
@@ -439,7 +456,7 @@ def test_flagsmith_uses_offline_handler_if_set_and_no_api_response(
     assert identity_flags.get_feature_value("some_feature") == "some-value"
 
 
-def test_cannot_use_offline_mode_without_offline_handler():
+def test_cannot_use_offline_mode_without_offline_handler() -> None:
     with pytest.raises(ValueError) as e:
         # When
         Flagsmith(offline_mode=True, offline_handler=None)
@@ -451,7 +468,7 @@ def test_cannot_use_offline_mode_without_offline_handler():
     )
 
 
-def test_cannot_use_default_handler_and_offline_handler(mocker):
+def test_cannot_use_default_handler_and_offline_handler(mocker: MockerFixture) -> None:
     # When
     with pytest.raises(ValueError) as e:
         Flagsmith(
@@ -468,7 +485,7 @@ def test_cannot_use_default_handler_and_offline_handler(mocker):
     )
 
 
-def test_cannot_create_flagsmith_client_in_remote_evaluation_without_api_key():
+def test_cannot_create_flagsmith_client_in_remote_evaluation_without_api_key() -> None:
     # When
     with pytest.raises(ValueError) as e:
         Flagsmith()
diff --git a/tests/test_offline_handlers.py b/tests/test_offline_handlers.py
index 862f173..b3cc597 100644
--- a/tests/test_offline_handlers.py
+++ b/tests/test_offline_handlers.py
@@ -5,7 +5,7 @@
 from flagsmith.offline_handlers import LocalFileHandler
 
 
-def test_local_file_handler(environment_json):
+def test_local_file_handler(environment_json: str) -> None:
     with patch("builtins.open", mock_open(read_data=environment_json)) as mock_file:
         # Given
         environment_document_file_path = "/some/path/environment.json"
diff --git a/tests/test_polling_manager.py b/tests/test_polling_manager.py
index 6cfcffd..c30df6f 100644
--- a/tests/test_polling_manager.py
+++ b/tests/test_polling_manager.py
@@ -2,12 +2,13 @@
 from unittest import mock
 
 import requests
+from pytest_mock import MockerFixture
 
 from flagsmith import Flagsmith
 from flagsmith.polling_manager import EnvironmentDataPollingManager
 
 
-def test_polling_manager_calls_update_environment_on_start():
+def test_polling_manager_calls_update_environment_on_start() -> None:
     # Given
     flagsmith = mock.MagicMock()
     polling_manager = EnvironmentDataPollingManager(
@@ -22,7 +23,7 @@ def test_polling_manager_calls_update_environment_on_start():
     polling_manager.stop()
 
 
-def test_polling_manager_calls_update_environment_on_each_refresh():
+def test_polling_manager_calls_update_environment_on_each_refresh() -> None:
     # Given
     flagsmith = mock.MagicMock()
     polling_manager = EnvironmentDataPollingManager(
@@ -40,7 +41,9 @@ def test_polling_manager_calls_update_environment_on_each_refresh():
     polling_manager.stop()
 
 
-def test_polling_manager_is_resilient_to_api_errors(mocker, server_api_key):
+def test_polling_manager_is_resilient_to_api_errors(
+    mocker: MockerFixture, server_api_key: str
+) -> None:
     # Given
     session_mock = mocker.patch("requests.Session")
     session_mock.get.return_value = mock.MagicMock(status_code=500)
@@ -56,7 +59,9 @@ def test_polling_manager_is_resilient_to_api_errors(mocker, server_api_key):
     polling_manager.stop()
 
 
-def test_polling_manager_is_resilient_to_request_exceptions(mocker, server_api_key):
+def test_polling_manager_is_resilient_to_request_exceptions(
+    mocker: MockerFixture, server_api_key: str
+) -> None:
     # Given
     session_mock = mocker.patch("requests.Session")
     session_mock.get.side_effect = requests.RequestException()
diff --git a/tests/test_streaming_manager.py b/tests/test_streaming_manager.py
index 136f40b..bd4bf93 100644
--- a/tests/test_streaming_manager.py
+++ b/tests/test_streaming_manager.py
@@ -1,6 +1,5 @@
 import time
 from datetime import datetime
-from typing import Generator
 from unittest.mock import MagicMock, Mock
 
 import pytest
@@ -14,7 +13,7 @@
 
 
 def test_stream_manager_handles_timeout(
-    mocked_responses: Generator["responses.RequestsMock", None, None]
+    mocked_responses: responses.RequestsMock,
 ) -> None:
     stream_url = (
         "https://realtime.flagsmith.com/sse/environments/B62qaMZNwfiqT76p38ggrQ/stream"
@@ -38,8 +37,8 @@ def test_stream_manager_handles_timeout(
 
 
 def test_stream_manager_handles_request_exception(
-    mocked_responses: Generator["responses.RequestsMock", None, None],
-    caplog: Generator["pytest.LogCaptureFixture", None, None],
+    mocked_responses: responses.RequestsMock,
+    caplog: pytest.LogCaptureFixture,
 ) -> None:
     stream_url = (
         "https://realtime.flagsmith.com/sse/environments/B62qaMZNwfiqT76p38ggrQ/stream"
@@ -78,13 +77,12 @@ def test_environment_updates_on_recent_event(
     flagsmith = Flagsmith(environment_key=server_api_key)
     flagsmith._environment = MagicMock()
     flagsmith._environment.updated_at = environment_updated_at
-
     flagsmith.handle_stream_event(
         event=Mock(
             data=f'{{"updated_at": {stream_updated_at.timestamp()}}}\n\n',
         )
     )
-
+    assert isinstance(flagsmith.update_environment, Mock)
     flagsmith.update_environment.assert_called_once()
 
 
@@ -105,7 +103,7 @@ def test_environment_does_not_update_on_past_event(
             data=f'{{"updated_at": {stream_updated_at.timestamp()}}}\n\n',
         )
     )
-
+    assert isinstance(flagsmith.update_environment, Mock)
     flagsmith.update_environment.assert_not_called()
 
 
@@ -126,7 +124,7 @@ def test_environment_does_not_update_on_same_event(
             data=f'{{"updated_at": {stream_updated_at.timestamp()}}}\n\n',
         )
     )
-
+    assert isinstance(flagsmith.update_environment, Mock)
     flagsmith.update_environment.assert_not_called()