diff --git a/plone/app/discussion/browser/comments.py b/plone/app/discussion/browser/comments.py
index 0c56651..02ca122 100644
--- a/plone/app/discussion/browser/comments.py
+++ b/plone/app/discussion/browser/comments.py
@@ -1,8 +1,6 @@
 from AccessControl import getSecurityManager
 from AccessControl import Unauthorized
 from Acquisition import aq_inner
-from datetime import datetime
-from datetime import timezone
 from DateTime import DateTime
 from plone.app.discussion import _
 from plone.app.discussion.browser.validator import CaptchaValidator
diff --git a/plone/app/discussion/comment.py b/plone/app/discussion/comment.py
index dc22187..c461048 100644
--- a/plone/app/discussion/comment.py
+++ b/plone/app/discussion/comment.py
@@ -5,11 +5,10 @@ from AccessControl.SecurityManagement import getSecurityManager
 from Acquisition import aq_base
 from Acquisition import aq_parent
 from Acquisition import Implicit
-from datetime import datetime
-from datetime import timezone
 from OFS.owner import Owned
 from OFS.role import RoleManager
 from OFS.Traversable import Traversable
+from datetime import timezone
 from persistent import Persistent
 from plone.app.discussion import _
 from plone.app.discussion.events import CommentAddedEvent
diff --git a/plone/app/discussion/tests/test_conversation.py b/plone/app/discussion/tests/test_conversation.py
index 569b5f3..ba70de9 100644
--- a/plone/app/discussion/tests/test_conversation.py
+++ b/plone/app/discussion/tests/test_conversation.py
@@ -80,8 +80,9 @@ class ConversationTest(unittest.TestCase):
         self.assertEqual(conversation.total_comments(), 1)
         self.assertTrue(
             datetime.now().astimezone(tz.gettz(default_timezone()))
-            - conversation.last_comment_date 
-            >= timedelta(seconds=0) <= timedelta(seconds=1),
+            - conversation.last_comment_date
+            >= timedelta(seconds=0)
+            <= timedelta(seconds=1),
         )
 
     def test_timezone_naive_comment(self):
@@ -94,24 +95,23 @@ class ConversationTest(unittest.TestCase):
         comment = createObject("plone.Comment")
         comment.text = "Comment text"
 
-        new_id = conversation.addComment(comment)
+        conversation.addComment(comment)
 
         # Check that comments have the correct portal timezones
-        self.assertTrue(comment.creation_date.tzinfo,
-                        tz.gettz("Europe/Berlin"))
-        self.assertTrue(comment.modification_date.tzinfo,
-                        tz.gettz("Europe/Berlin"))
-        
+        self.assertTrue(comment.creation_date.tzinfo, tz.gettz("Europe/Berlin"))
+        self.assertTrue(comment.modification_date.tzinfo, tz.gettz("Europe/Berlin"))
+
         # Remove the timezone from the comment dates
         comment.creation_date = datetime.utcnow()
         comment.modification_date = datetime.utcnow()
-        
+
         # Check that the timezone naive date is converted to UTC
         # See https://github.com/plone/plone.app.discussion/pull/204
         self.assertTrue(
-            datetime.utcnow().replace(tzinfo=timezone.utc) 
-            - conversation.last_comment_date 
-            >= timedelta(seconds=0) <= timedelta(seconds=1),
+            datetime.utcnow().replace(tzinfo=timezone.utc)
+            - conversation.last_comment_date
+            >= timedelta(seconds=0)
+            <= timedelta(seconds=1),
         )
         self.assertTrue(comment.creation_date.tzinfo, timezone.utc)
         self.assertTrue(comment.modification_date.tzinfo, timezone.utc)
@@ -531,20 +531,23 @@ class ConversationTest(unittest.TestCase):
         # swapped in
         comment1 = createObject("plone.Comment")
         comment1.text = "Comment text"
-        comment1.creation_date =\
-            datetime.now().astimezone(tz.gettz(default_timezone())) - timedelta(4)
+        comment1.creation_date = datetime.now().astimezone(
+            tz.gettz(default_timezone())
+        ) - timedelta(4)
         conversation.addComment(comment1)
 
         comment2 = createObject("plone.Comment")
         comment2.text = "Comment text"
-        comment2.creation_date =\
-            datetime.now().astimezone(tz.gettz(default_timezone())) - timedelta(2)
+        comment2.creation_date = datetime.now().astimezone(
+            tz.gettz(default_timezone())
+        ) - timedelta(2)
         new_comment2_id = conversation.addComment(comment2)
 
         comment3 = createObject("plone.Comment")
         comment3.text = "Comment text"
-        comment3.creation_date =\
-            datetime.now().astimezone(tz.gettz(default_timezone())) - timedelta(1)
+        comment3.creation_date = datetime.now().astimezone(
+            tz.gettz(default_timezone())
+        ) - timedelta(1)
         new_comment3_id = conversation.addComment(comment3)
 
         # check if the latest comment is exactly one day old
diff --git a/plone/app/discussion/tests/test_indexers.py b/plone/app/discussion/tests/test_indexers.py
index 79c81a0..5944b85 100644
--- a/plone/app/discussion/tests/test_indexers.py
+++ b/plone/app/discussion/tests/test_indexers.py
@@ -4,10 +4,8 @@ from .. import catalog
 from ..interfaces import IConversation
 from ..testing import PLONE_APP_DISCUSSION_INTEGRATION_TESTING  # noqa
 from datetime import datetime
-from datetime import timezone
 from dateutil import tz
 from DateTime import DateTime
-from plone.app.event.base import localized_now
 from plone.app.event.base import default_timezone
 from plone.app.testing import setRoles
 from plone.app.testing import TEST_USER_ID
@@ -16,8 +14,6 @@ from plone.registry.interfaces import IRegistry
 from zope.component import createObject
 from zope.component import getUtility
 
-import time
-import os
 import unittest
 
 
@@ -147,10 +143,10 @@ class CommentIndexersTest(unittest.TestCase):
         comment.text = "Lorem ipsum dolor sit amet."
         comment.creator = "jim"
         comment.author_name = "Jim"
-        
+
         # Create date in CEST (ie not daylight savings = UTC+2)
         comment.creation_date = datetime(2006, 9, 17, 14, 18, 12).replace(tzinfo=tz.gettz("Europe/Berlin"))
-        
+
         # Create date in CET (ie daylight savings = UTC+1)
         comment.modification_date = datetime(2008, 3, 12, 7, 32, 52).replace(tzinfo=tz.gettz("Europe/Berlin"))