diff --git a/python/nav/Snmp/__init__.py b/python/nav/Snmp/__init__.py
index 83097c6076..df0d7daaab 100644
--- a/python/nav/Snmp/__init__.py
+++ b/python/nav/Snmp/__init__.py
@@ -27,7 +27,7 @@
 
 try:
     # our highest preference is pynetsnmp, since it can support IPv6
-    import pynetsnmp
+    import pynetsnmp  # noqa: F401 - needed to set BACKEND
 except ImportError:
     pass
 else:
diff --git a/python/nav/asyncdns.py b/python/nav/asyncdns.py
index 3280560323..9f803c3a6b 100644
--- a/python/nav/asyncdns.py
+++ b/python/nav/asyncdns.py
@@ -44,6 +44,23 @@
 from twisted.names.error import DNSServerError, DNSNameError
 from twisted.names.error import DNSNotImplementedError, DNSQueryRefusedError
 
+__all__ = [
+    "reverse_lookup",
+    "forward_lookup",
+    "Resolver",
+    "ForwardResolver",
+    "ReverseResolver",
+    "DNSUnknownError",
+    "DomainError",
+    "AuthoritativeDomainError",
+    "DNSQueryTimeoutError",
+    "DNSFormatError",
+    "DNSServerError",
+    "DNSNameError",
+    "DNSNotImplementedError",
+    "DNSQueryRefusedError",
+]
+
 
 BATCH_SIZE = 100
 
diff --git a/python/nav/bin/navcheckservice.py b/python/nav/bin/navcheckservice.py
index 5a27107953..3aa6cb08f7 100755
--- a/python/nav/bin/navcheckservice.py
+++ b/python/nav/bin/navcheckservice.py
@@ -31,7 +31,6 @@
 
 from nav.logs import init_stderr_logging
 from nav.statemon import checkermap
-import nav.statemon.checker  # necessary for relative imports on python3
 
 
 _logger = logging.getLogger('nav.checkservice')
diff --git a/python/nav/debug.py b/python/nav/debug.py
index 2c68569ea8..383079c06f 100644
--- a/python/nav/debug.py
+++ b/python/nav/debug.py
@@ -98,7 +98,7 @@ def log_last_django_query(logger):
 
     :param logger: The logging.Logger object to use for logging.
     """
-    from nav.models import manage as _manage
+    from nav.models import manage as _manage  # noqa: F401 - import needed for debugging
     from django.db import connection
 
     if connection.queries:
diff --git a/python/nav/ipdevpoll/shadows/__init__.py b/python/nav/ipdevpoll/shadows/__init__.py
index a231239f5f..69ceb53d8b 100644
--- a/python/nav/ipdevpoll/shadows/__init__.py
+++ b/python/nav/ipdevpoll/shadows/__init__.py
@@ -43,6 +43,38 @@
 from .prefix import Prefix
 from .gwpeers import GatewayPeerSession
 
+__all__ = [
+    "NetboxType",
+    "NetboxInfo",
+    "Vendor",
+    "Module",
+    "Device",
+    "Location",
+    "Room",
+    "Category",
+    "Organization",
+    "Usage",
+    "Vlan",
+    "GwPortPrefix",
+    "NetType",
+    "SwPortVlan",
+    "Arp",
+    "SwPortAllowedVlan",
+    "Sensor",
+    "PowerSupplyOrFan",
+    "POEPort",
+    "POEGroup",
+    "Interface",
+    "InterfaceStack",
+    "InterfaceAggregate",
+    "SwPortBlocked",
+    "Cam",
+    "AdjacencyCandidate",
+    "UnrecognizedNeighbor",
+    "NetboxEntity",
+    "GatewayPeerSession",
+]
+
 # Shadow classes.  Not all of these will be used to store data, but
 # may be used to retrieve and cache existing database records.
 
diff --git a/python/nav/ipdevpoll/snmp/__init__.py b/python/nav/ipdevpoll/snmp/__init__.py
index 01020a2ff6..f6fadd9e43 100644
--- a/python/nav/ipdevpoll/snmp/__init__.py
+++ b/python/nav/ipdevpoll/snmp/__init__.py
@@ -15,12 +15,17 @@
 #
 """selects a proper SNMP backend for ipdevpoll"""
 
-
 try:
-    import pynetsnmp.twistedsnmp
+    import pynetsnmp.twistedsnmp  # noqa: F401 - unused imports
 except ImportError:
     raise ImportError("No supported SNMP backend was found")
 else:
     from nav.ipdevpoll.snmp.pynetsnmp import AgentProxy, snmpprotocol
 
 from .common import SnmpError
+
+__all__ = [
+    "AgentProxy",
+    "snmpprotocol",
+    "SnmpError",
+]
diff --git a/python/nav/smsd/uninettmaildispatcher.py b/python/nav/smsd/uninettmaildispatcher.py
index d36aacbf71..e5778c93dc 100644
--- a/python/nav/smsd/uninettmaildispatcher.py
+++ b/python/nav/smsd/uninettmaildispatcher.py
@@ -25,8 +25,6 @@
 
 from django.core.mail import EmailMessage
 
-# pylint: disable=unused-import
-from nav import models as _  # ensure Django is setup for NAV
 from nav.smsd.dispatcher import Dispatcher, DispatcherError
 
 
diff --git a/python/nav/web/geomap/features.py b/python/nav/web/geomap/features.py
index 9e749d0980..0324d17410 100644
--- a/python/nav/web/geomap/features.py
+++ b/python/nav/web/geomap/features.py
@@ -41,7 +41,7 @@
 
 # is_nan must be available in the global namespace for the proper evaluation of
 # some indicator rules
-from nav.web.geomap.utils import union_dict, subdict, concat_list, is_nan
+from nav.web.geomap.utils import union_dict, subdict, concat_list, is_nan  # noqa: F401
 
 _logger = logging.getLogger('nav.web.geomap.features')
 
diff --git a/tests/unittests/web/ldapauth_test.py b/tests/unittests/web/ldapauth_test.py
index 6833ee086a..070140e999 100644
--- a/tests/unittests/web/ldapauth_test.py
+++ b/tests/unittests/web/ldapauth_test.py
@@ -1,12 +1,12 @@
+import importlib.util
 import pytest
 
 from nav.config import NAVConfigParser
 from nav.web.auth.ldap import LDAPUser, open_ldap
 from mock import Mock, patch
 
-try:
-    import ldap
-except ImportError:
+found = importlib.util.find_spec('ldap')
+if not found:
     pytestmark = pytest.mark.skip(reason="ldap module is not available")