diff --git a/thunorweb/apps.py b/thunorweb/apps.py
index e4bf659a..850ce1cf 100644
--- a/thunorweb/apps.py
+++ b/thunorweb/apps.py
@@ -3,7 +3,7 @@
 from django.apps import AppConfig
 from django.conf import settings
 from django.db.models.signals import post_save
-from django.db.utils import ProgrammingError, OperationalError, DatabaseError
+from django.db.utils import ProgrammingError, OperationalError
 
 
 class ThunorConfig(AppConfig):
diff --git a/thunorweb/tasks.py b/thunorweb/tasks.py
index 23d5f621..0d56a27f 100644
--- a/thunorweb/tasks.py
+++ b/thunorweb/tasks.py
@@ -431,7 +431,7 @@ def _dataset_groupings(dataset, regenerate_cache=False):
     missing_combos = []
     for cl in cell_line_ids:
         for dr in drug_ids:
-            if not (cl, dr) in combos:
+            if (cl, dr) not in combos:
                 missing_combos.append((str(cl), (str(dr), )))
 
     if has_drug_combos:
diff --git a/thunorweb/views/dataset_downloads.py b/thunorweb/views/dataset_downloads.py
index 87b42ecb..56bcde16 100644
--- a/thunorweb/views/dataset_downloads.py
+++ b/thunorweb/views/dataset_downloads.py
@@ -11,7 +11,7 @@
 from django.conf import settings
 import os
 from thunorweb.serve_file import serve_file
-from thunorweb.views.datasets import license_accepted, LICENSE_UNSIGNED
+from thunorweb.views.datasets import license_accepted
 from django.views.decorators.clickjacking import xframe_options_sameorigin
 from thunorweb.views import login_required_unless_public, _assert_has_perm
 
diff --git a/thunorweb/views/plate_mapper.py b/thunorweb/views/plate_mapper.py
index 2fcf04da..33b37c8f 100644
--- a/thunorweb/views/plate_mapper.py
+++ b/thunorweb/views/plate_mapper.py
@@ -192,7 +192,7 @@ def ajax_save_plate(request):
         wells_to_insert = []
         for plate in plate_ids:
             for well_num, cell_line_id in enumerate(cell_line_ids):
-                if not (plate, well_num) in existing_wells:
+                if (plate, well_num) not in existing_wells:
                     wells_to_insert.append(Well(
                         well_num=well_num,
                         plate_id=plate,
diff --git a/thunorweb/views/plots.py b/thunorweb/views/plots.py
index 11a166a1..211dad99 100644
--- a/thunorweb/views/plots.py
+++ b/thunorweb/views/plots.py
@@ -1,5 +1,5 @@
 from django.shortcuts import render, Http404
-from django.http import JsonResponse, HttpResponse
+from django.http import HttpResponse
 from django.utils.html import strip_tags
 from django.views.decorators.csrf import ensure_csrf_cookie
 from django.core.cache import cache
diff --git a/thunorweb/views/tags.py b/thunorweb/views/tags.py
index 2686fa94..0781f85c 100644
--- a/thunorweb/views/tags.py
+++ b/thunorweb/views/tags.py
@@ -3,7 +3,7 @@
 from django.db import transaction
 from django.db.models import Q
 from thunorweb.models import CellLine, Drug, CellLineTag, DrugTag
-from thunorweb.views import login_required_unless_public, login_required
+from thunorweb.views import login_required_unless_public
 import logging
 import pandas as pd
 from django.db.utils import IntegrityError