diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index a710a5ff..f9da16d5 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -7,12 +7,11 @@ repos:
     -   id: check-merge-conflict
     -   id: check-yaml
     -   id: debug-statements
-# TDOO Enable in separate PR
-#     -   id: end-of-file-fixer
-#         exclude: ^docs/.*$
-#     -   id: trailing-whitespace
-#         exclude: README.md
-# -   repo: git://github.com/PyCQA/flake8
-#     rev: 88caf5ac484f5c09aedc02167c59c66ff0af0068  # 3.7.7
-#     hooks:
-#     -   id: flake8
+    -   id: end-of-file-fixer
+        exclude: ^docs/.*$
+    -   id: trailing-whitespace
+        exclude: README.md
+-   repo: git://github.com/PyCQA/flake8
+    rev: 88caf5ac484f5c09aedc02167c59c66ff0af0068  # 3.7.7
+    hooks:
+    -   id: flake8
diff --git a/docs/examples.rst b/docs/examples.rst
index 45fa3c55..283a0f5e 100644
--- a/docs/examples.rst
+++ b/docs/examples.rst
@@ -37,14 +37,14 @@ Search all Models with Union
     class Query(graphene.ObjectType):
         node = relay.Node.Field()
         search = graphene.List(SearchResult, q=graphene.String())  # List field for search results
-        
+
         # Normal Fields
         all_books = SQLAlchemyConnectionField(BookConnection)
         all_authors = SQLAlchemyConnectionField(AuthorConnection)
 
         def resolve_search(self, info, **args):
             q = args.get("q")  # Search query
-            
+
             # Get queries
             bookdata_query = BookData.get_query(info)
             author_query = Author.get_query(info)
@@ -53,14 +53,14 @@ Search all Models with Union
             books = bookdata_query.filter((BookModel.title.contains(q)) |
                                           (BookModel.isbn.contains(q)) |
                                           (BookModel.authors.any(AuthorModel.name.contains(q)))).all()
-            
+
             # Query Authors
             authors = author_query.filter(AuthorModel.name.contains(q)).all()
 
             return authors + books  # Combine lists
 
     schema = graphene.Schema(query=Query, types=[Book, Author, SearchResult])
-    
+
 Example GraphQL query
 
 .. code::
diff --git a/docs/tips.rst b/docs/tips.rst
index cb25bd48..1fd39107 100644
--- a/docs/tips.rst
+++ b/docs/tips.rst
@@ -31,7 +31,7 @@ If you don't specify any, the following error will be displayed:
 Sorting
 -------
 
-By default the SQLAlchemyConnectionField sorts the result elements over the primary key(s). 
+By default the SQLAlchemyConnectionField sorts the result elements over the primary key(s).
 The query has a `sort` argument which allows to sort over a different column(s)
 
 Given the model
diff --git a/examples/nameko_sqlalchemy/README.md b/examples/nameko_sqlalchemy/README.md
index f60ccb00..39cfe925 100644
--- a/examples/nameko_sqlalchemy/README.md
+++ b/examples/nameko_sqlalchemy/README.md
@@ -51,4 +51,4 @@ Now the following command will setup the database, and start the server:
 
 Now head on over to postman and send POST request to:
 [http://127.0.0.1:5000/graphql](http://127.0.0.1:5000/graphql)
-and run some queries!
\ No newline at end of file
+and run some queries!
diff --git a/examples/nameko_sqlalchemy/app.py b/examples/nameko_sqlalchemy/app.py
index f7fe150a..18302ce6 100755
--- a/examples/nameko_sqlalchemy/app.py
+++ b/examples/nameko_sqlalchemy/app.py
@@ -19,7 +19,7 @@ def query(self, request):
               execution_results,
               format_error=default_format_error,is_batch=False, encode=json_encode)
       return result
-  
+
   def parse_body(self,request):
       # We use mimetype here since we don't need the other
       # information provided by content_type
@@ -33,4 +33,4 @@ def parse_body(self,request):
       elif content_type in ('application/x-www-form-urlencoded', 'multipart/form-data'):
           return request.form
 
-      return {}
\ No newline at end of file
+      return {}
diff --git a/examples/nameko_sqlalchemy/config.yml b/examples/nameko_sqlalchemy/config.yml
index cdea553c..8ca6a45c 100644
--- a/examples/nameko_sqlalchemy/config.yml
+++ b/examples/nameko_sqlalchemy/config.yml
@@ -1 +1 @@
-WEB_SERVER_ADDRESS: '0.0.0.0:5000'
\ No newline at end of file
+WEB_SERVER_ADDRESS: '0.0.0.0:5000'
diff --git a/examples/nameko_sqlalchemy/requirements.txt b/examples/nameko_sqlalchemy/requirements.txt
index 1f7be7db..be037f73 100644
--- a/examples/nameko_sqlalchemy/requirements.txt
+++ b/examples/nameko_sqlalchemy/requirements.txt
@@ -1,4 +1,4 @@
 graphene[sqlalchemy]
 SQLAlchemy==1.0.11
 nameko
-graphql-server-core
\ No newline at end of file
+graphql-server-core
diff --git a/examples/nameko_sqlalchemy/run.sh b/examples/nameko_sqlalchemy/run.sh
index d3953677..bfe17d9a 100755
--- a/examples/nameko_sqlalchemy/run.sh
+++ b/examples/nameko_sqlalchemy/run.sh
@@ -1,4 +1,4 @@
 #!/bin/sh
 echo "Starting application service server"
 # Run Service
-nameko run --config config.yml service
\ No newline at end of file
+nameko run --config config.yml service
diff --git a/examples/nameko_sqlalchemy/service.py b/examples/nameko_sqlalchemy/service.py
index 394764e4..d83ab861 100644
--- a/examples/nameko_sqlalchemy/service.py
+++ b/examples/nameko_sqlalchemy/service.py
@@ -1,11 +1,11 @@
 #!/usr/bin/env python
 from nameko.web.handlers import http
-from app import App 
+from app import App
 
 
 class DepartmentService:
-    name = 'department'    
+    name = 'department'
 
     @http('POST', '/graphql')
     def query(self, request):
-        return App().query(request)
\ No newline at end of file
+        return App().query(request)
diff --git a/graphene_sqlalchemy/tests/test_converter.py b/graphene_sqlalchemy/tests/test_converter.py
index c2ec3e49..c6c49bba 100644
--- a/graphene_sqlalchemy/tests/test_converter.py
+++ b/graphene_sqlalchemy/tests/test_converter.py
@@ -168,7 +168,7 @@ class Test(Base):
         )
 
     graphene_type = convert_sqlalchemy_column(Test.column)
-    assert graphene_type.kwargs["required"] == False
+    assert not graphene_type.kwargs["required"]
 
 
 def test_should_scalar_list_convert_list():
@@ -343,4 +343,3 @@ def __init__(self, col1, col2):
         )
 
     assert "Don't know how to convert the composite field" in str(excinfo.value)
-
diff --git a/graphene_sqlalchemy/tests/test_query.py b/graphene_sqlalchemy/tests/test_query.py
index f1116d9d..8bb4891c 100644
--- a/graphene_sqlalchemy/tests/test_query.py
+++ b/graphene_sqlalchemy/tests/test_query.py
@@ -555,4 +555,3 @@ def makeNodes(nodeList):
         assert set(node["node"]["name"] for node in value["edges"]) == set(
             node["node"]["name"] for node in expectedNoSort[key]["edges"]
         )
-
diff --git a/graphene_sqlalchemy/tests/test_reflected.py b/graphene_sqlalchemy/tests/test_reflected.py
index c8a1a70f..46e10de9 100644
--- a/graphene_sqlalchemy/tests/test_reflected.py
+++ b/graphene_sqlalchemy/tests/test_reflected.py
@@ -18,4 +18,3 @@ def test_objecttype_registered():
     assert issubclass(Reflected, ObjectType)
     assert Reflected._meta.model == ReflectedEditor
     assert list(Reflected._meta.fields.keys()) == ["editor_id", "name"]
-
diff --git a/graphene_sqlalchemy/tests/test_schema.py b/graphene_sqlalchemy/tests/test_schema.py
index 909570a6..628da185 100644
--- a/graphene_sqlalchemy/tests/test_schema.py
+++ b/graphene_sqlalchemy/tests/test_schema.py
@@ -47,4 +47,3 @@ class Meta:
             model = Reporter
             only_fields = ("id", "email")
     assert list(Reporter2._meta.fields.keys()) == ["id", "email"]
-
diff --git a/graphene_sqlalchemy/tests/test_types.py b/graphene_sqlalchemy/tests/test_types.py
index c11ec351..b6dce726 100644
--- a/graphene_sqlalchemy/tests/test_types.py
+++ b/graphene_sqlalchemy/tests/test_types.py
@@ -1,7 +1,7 @@
 from collections import OrderedDict
 from graphene import Field, Int, Interface, ObjectType
 from graphene.relay import Node, is_node, Connection
-import six
+import six  # noqa F401
 from promise import Promise
 
 from ..registry import Registry
@@ -176,7 +176,9 @@ class TestConnection(Connection):
         class Meta:
             node = ReporterWithCustomOptions
 
-    resolver = lambda *args, **kwargs: Promise.resolve([])
+    def resolver(*args, **kwargs):
+        return Promise.resolve([])
+
     result = SQLAlchemyConnectionField.connection_resolver(
         resolver, TestConnection, ReporterWithCustomOptions, None, None
     )
diff --git a/graphene_sqlalchemy/types.py b/graphene_sqlalchemy/types.py
index e8a05c8f..300af684 100644
--- a/graphene_sqlalchemy/types.py
+++ b/graphene_sqlalchemy/types.py
@@ -1,5 +1,6 @@
 from collections import OrderedDict
 
+import sqlalchemy
 from sqlalchemy.inspection import inspect as sqlalchemyinspect
 from sqlalchemy.ext.hybrid import hybrid_property
 from sqlalchemy.orm.exc import NoResultFound
@@ -80,9 +81,9 @@ def construct_fields(model, registry, only_fields, exclude_fields):
 
 
 class SQLAlchemyObjectTypeOptions(ObjectTypeOptions):
-    model = None  # type: Model
-    registry = None  # type: Registry
-    connection = None  # type: Type[Connection]
+    model = None  # type: sqlalchemy.Model
+    registry = None  # type: sqlalchemy.Registry
+    connection = None  # type: sqlalchemy.Type[sqlalchemy.Connection]
     id = None  # type: str