55 files changed, 147 insertions, 67 deletions

diff --git a/src/mailman/app/tests/test_lifecycle.py b/src/mailman/app/tests/test_lifecycle.py
index d4ad067d2..a3a186f6f 100644
--- a/src/mailman/app/tests/test_lifecycle.py
+++ b/src/mailman/app/tests/test_lifecycle.py
@@ -21,10 +21,10 @@ import os
 import shutil
 import unittest
 
+from mailman.app.lifecycle import create_list, remove_list
 from mailman.interfaces.address import InvalidEmailAddressError
 from mailman.interfaces.domain import BadDomainSpecificationError
 from mailman.interfaces.listmanager import IListManager
-from mailman.app.lifecycle import create_list, remove_list
 from mailman.testing.layers import ConfigLayer
 from zope.component import getUtility
 
diff --git a/src/mailman/app/tests/test_subscriptions.py b/src/mailman/app/tests/test_subscriptions.py
index 02b5fe6da..1139591de 100644
--- a/src/mailman/app/tests/test_subscriptions.py
+++ b/src/mailman/app/tests/test_subscriptions.py
@@ -22,14 +22,14 @@ import unittest
 from mailman.app.lifecycle import create_list
 from mailman.app.subscriptions import SubscriptionWorkflow
 from mailman.interfaces.bans import IBanManager
+from mailman.interfaces.mailinglist import SubscriptionPolicy
 from mailman.interfaces.member import MembershipIsBannedError
 from mailman.interfaces.pending import IPendings
 from mailman.interfaces.subscriptions import TokenOwner
+from mailman.interfaces.usermanager import IUserManager
 from mailman.testing.helpers import (
     LogFileMark, get_queue_messages, set_preferred)
 from mailman.testing.layers import ConfigLayer
-from mailman.interfaces.mailinglist import SubscriptionPolicy
-from mailman.interfaces.usermanager import IUserManager
 from mailman.utilities.datetime import now
 from unittest.mock import patch
 from zope.component import getUtility
diff --git a/src/mailman/archiving/tests/test_mhonarc.py b/src/mailman/archiving/tests/test_mhonarc.py
index 803875bd4..993a14c1c 100644
--- a/src/mailman/archiving/tests/test_mhonarc.py
+++ b/src/mailman/archiving/tests/test_mhonarc.py
@@ -23,8 +23,8 @@ import shutil
 import tempfile
 import unittest
 
-from mailman.archiving.mhonarc import MHonArc
 from mailman.app.lifecycle import create_list
+from mailman.archiving.mhonarc import MHonArc
 from mailman.database.transaction import transaction
 from mailman.testing.helpers import (
     configuration, specialized_message_from_string as mfs)
diff --git a/src/mailman/archiving/tests/test_prototype.py b/src/mailman/archiving/tests/test_prototype.py
index 54fbc06af..32dec0729 100644
--- a/src/mailman/archiving/tests/test_prototype.py
+++ b/src/mailman/archiving/tests/test_prototype.py
@@ -29,9 +29,8 @@ from mailman.app.lifecycle import create_list
 from mailman.archiving.prototype import Prototype
 from mailman.config import config
 from mailman.database.transaction import transaction
-from mailman.testing.helpers import LogFileMark
 from mailman.testing.helpers import (
-    specialized_message_from_string as mfs)
+    LogFileMark, specialized_message_from_string as mfs)
 from mailman.testing.layers import ConfigLayer
 from mailman.utilities.email import add_message_hash
 
diff --git a/src/mailman/commands/cli_import.py b/src/mailman/commands/cli_import.py
index ecb879a5a..126c026d0 100644
--- a/src/mailman/commands/cli_import.py
+++ b/src/mailman/commands/cli_import.py
@@ -26,7 +26,7 @@ from mailman.core.i18n import _
 from mailman.database.transaction import transactional
 from mailman.interfaces.command import ICLISubCommand
 from mailman.interfaces.listmanager import IListManager
-from mailman.utilities.importer import import_config_pck, Import21Error
+from mailman.utilities.importer import Import21Error, import_config_pck
 from zope.component import getUtility
 from zope.interface import implementer
 
diff --git a/src/mailman/commands/tests/test_control.py b/src/mailman/commands/tests/test_control.py
index b25c63185..26d921cd7 100644
--- a/src/mailman/commands/tests/test_control.py
+++ b/src/mailman/commands/tests/test_control.py
@@ -21,13 +21,13 @@ import os
 import sys
 import time
 import errno
-import signal
 import shutil
+import signal
 import socket
 import unittest
 
 from contextlib import ExitStack, suppress
-from datetime import timedelta, datetime
+from datetime import datetime, timedelta
 from mailman.commands.cli_control import Start, kill_watcher
 from mailman.config import Configuration, config
 from mailman.testing.helpers import configuration
diff --git a/src/mailman/database/alembic/env.py b/src/mailman/database/alembic/env.py
index 7cda59e82..e97b05d5c 100644
--- a/src/mailman/database/alembic/env.py
+++ b/src/mailman/database/alembic/env.py
@@ -20,8 +20,8 @@
 from alembic import context
 from contextlib import closing
 from mailman import public
-from mailman.core.initialize import initialize_1
 from mailman.config import config
+from mailman.core.initialize import initialize_1
 from mailman.database.model import Model
 from mailman.utilities.string import expand
 from sqlalchemy import create_engine
diff --git a/src/mailman/database/alembic/versions/16c2b25c7b_list_subscription_policy.py b/src/mailman/database/alembic/versions/16c2b25c7b_list_subscription_policy.py
index 1358b99aa..fef188bd0 100644
--- a/src/mailman/database/alembic/versions/16c2b25c7b_list_subscription_policy.py
+++ b/src/mailman/database/alembic/versions/16c2b25c7b_list_subscription_policy.py
@@ -6,11 +6,11 @@ Create Date: 2015-03-21 11:00:44.634883
 
 """
 
-from alembic import op
 import sqlalchemy as sa
 
+from alembic import op
+from mailman.database.helpers import exists_in_db, is_sqlite
 from mailman.database.types import Enum
-from mailman.database.helpers import is_sqlite, exists_in_db
 from mailman.interfaces.mailinglist import SubscriptionPolicy
 
 
diff --git a/src/mailman/database/alembic/versions/42756496720_header_matches.py b/src/mailman/database/alembic/versions/42756496720_header_matches.py
index d197d5959..4514fb398 100644
--- a/src/mailman/database/alembic/versions/42756496720_header_matches.py
+++ b/src/mailman/database/alembic/versions/42756496720_header_matches.py
@@ -9,7 +9,7 @@ Create Date: 2015-09-11 10:11:38.310315
 import sqlalchemy as sa
 
 from alembic import op
-from mailman.database.helpers import is_sqlite, exists_in_db
+from mailman.database.helpers import exists_in_db, is_sqlite
 
 
 # Revision identifiers, used by Alembic.
diff --git a/src/mailman/database/alembic/versions/46e92facee7_add_serverowner_domainowner.py b/src/mailman/database/alembic/versions/46e92facee7_add_serverowner_domainowner.py
index 01a08d7d2..1c689670a 100644
--- a/src/mailman/database/alembic/versions/46e92facee7_add_serverowner_domainowner.py
+++ b/src/mailman/database/alembic/versions/46e92facee7_add_serverowner_domainowner.py
@@ -26,7 +26,7 @@ Create Date: 2015-03-20 16:01:25.007242
 import sqlalchemy as sa
 
 from alembic import op
-from mailman.database.helpers import is_sqlite, exists_in_db
+from mailman.database.helpers import exists_in_db, is_sqlite
 
 
 # Revision identifiers, used by Alembic.
diff --git a/src/mailman/database/alembic/versions/51b7f92bd06c_initial.py b/src/mailman/database/alembic/versions/51b7f92bd06c_initial.py
index 6252e1f23..aa7ea765d 100644
--- a/src/mailman/database/alembic/versions/51b7f92bd06c_initial.py
+++ b/src/mailman/database/alembic/versions/51b7f92bd06c_initial.py
@@ -32,7 +32,7 @@ Create Date: 2014-10-10 09:53:35.624472
 import sqlalchemy as sa
 
 from alembic import op
-from mailman.database.helpers import is_sqlite, exists_in_db
+from mailman.database.helpers import exists_in_db, is_sqlite
 
 
 # Revision identifiers, used by Alembic.
diff --git a/src/mailman/database/tests/test_factory.py b/src/mailman/database/tests/test_factory.py
index 0c2e595c9..d8593cc76 100644
--- a/src/mailman/database/tests/test_factory.py
+++ b/src/mailman/database/tests/test_factory.py
@@ -26,8 +26,8 @@ from mailman.database.factory import LAST_STORM_SCHEMA_VERSION, SchemaManager
 from mailman.database.model import Model
 from mailman.interfaces.database import DatabaseError
 from mailman.testing.layers import ConfigLayer
-from sqlalchemy import MetaData, Table, Column, Integer, Unicode
-from sqlalchemy.exc import ProgrammingError, OperationalError
+from sqlalchemy import Column, Integer, MetaData, Table, Unicode
+from sqlalchemy.exc import OperationalError, ProgrammingError
 from sqlalchemy.schema import Index
 from unittest.mock import patch
 
diff --git a/src/mailman/database/types.py b/src/mailman/database/types.py
index 343ee0461..28b261514 100644
--- a/src/mailman/database/types.py
+++ b/src/mailman/database/types.py
@@ -22,7 +22,7 @@ import uuid
 from mailman import public
 from sqlalchemy import Integer
 from sqlalchemy.dialects import postgresql
-from sqlalchemy.types import TypeDecorator, CHAR
+from sqlalchemy.types import CHAR, TypeDecorator
 
 
 @public
diff --git a/src/mailman/handlers/rfc_2369.py b/src/mailman/handlers/rfc_2369.py
index 3daf6414d..59c618da8 100644
--- a/src/mailman/handlers/rfc_2369.py
+++ b/src/mailman/handlers/rfc_2369.py
@@ -24,8 +24,8 @@ from mailman import public
 from mailman.core.i18n import _
 from mailman.handlers.cook_headers import uheader
 from mailman.interfaces.archiver import ArchivePolicy
-from mailman.interfaces.mailinglist import IListArchiverSet
 from mailman.interfaces.handler import IHandler
+from mailman.interfaces.mailinglist import IListArchiverSet
 from zope.interface import implementer
 
 
diff --git a/src/mailman/interfaces/address.py b/src/mailman/interfaces/address.py
index 19a9d930c..8a1ac81d5 100644
--- a/src/mailman/interfaces/address.py
+++ b/src/mailman/interfaces/address.py
@@ -19,7 +19,7 @@
 
 from mailman import public
 from mailman.interfaces.errors import MailmanError
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/archiver.py b/src/mailman/interfaces/archiver.py
index 9a210d74e..cd10b22e3 100644
--- a/src/mailman/interfaces/archiver.py
+++ b/src/mailman/interfaces/archiver.py
@@ -19,7 +19,7 @@
 
 from enum import Enum
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/autorespond.py b/src/mailman/interfaces/autorespond.py
index 7f6d44711..a67cf6aaf 100644
--- a/src/mailman/interfaces/autorespond.py
+++ b/src/mailman/interfaces/autorespond.py
@@ -20,7 +20,7 @@
 from datetime import timedelta
 from enum import Enum
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 ALWAYS_REPLY = timedelta()
diff --git a/src/mailman/interfaces/chain.py b/src/mailman/interfaces/chain.py
index 3fccb4090..0af9bf8e5 100644
--- a/src/mailman/interfaces/chain.py
+++ b/src/mailman/interfaces/chain.py
@@ -19,7 +19,7 @@
 
 from enum import Enum
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/command.py b/src/mailman/interfaces/command.py
index 76bf8aa1c..95719b504 100644
--- a/src/mailman/interfaces/command.py
+++ b/src/mailman/interfaces/command.py
@@ -19,7 +19,7 @@
 
 from enum import Enum
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/digests.py b/src/mailman/interfaces/digests.py
index 0bff36ec4..cff838284 100644
--- a/src/mailman/interfaces/digests.py
+++ b/src/mailman/interfaces/digests.py
@@ -19,7 +19,7 @@
 
 from enum import Enum
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/domain.py b/src/mailman/interfaces/domain.py
index eef391071..7be5909a9 100644
--- a/src/mailman/interfaces/domain.py
+++ b/src/mailman/interfaces/domain.py
@@ -19,7 +19,7 @@
 
 from mailman import public
 from mailman.interfaces.errors import MailmanError
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/languages.py b/src/mailman/interfaces/languages.py
index 129b5e1df..b45083575 100644
--- a/src/mailman/interfaces/languages.py
+++ b/src/mailman/interfaces/languages.py
@@ -18,7 +18,7 @@
 """Interfaces for managing languages."""
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/listmanager.py b/src/mailman/interfaces/listmanager.py
index 0887248b2..fddec06c8 100644
--- a/src/mailman/interfaces/listmanager.py
+++ b/src/mailman/interfaces/listmanager.py
@@ -19,7 +19,7 @@
 
 from mailman import public
 from mailman.interfaces.errors import MailmanError
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/mailinglist.py b/src/mailman/interfaces/mailinglist.py
index 4ccf97a6d..911d958f5 100644
--- a/src/mailman/interfaces/mailinglist.py
+++ b/src/mailman/interfaces/mailinglist.py
@@ -20,7 +20,7 @@
 from enum import Enum
 from mailman import public
 from mailman.interfaces.member import MemberRole
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/member.py b/src/mailman/interfaces/member.py
index dd8d3f383..367838e21 100644
--- a/src/mailman/interfaces/member.py
+++ b/src/mailman/interfaces/member.py
@@ -20,7 +20,7 @@
 from enum import Enum
 from mailman import public
 from mailman.interfaces.errors import MailmanError
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/messages.py b/src/mailman/interfaces/messages.py
index cd05722c9..2ea2aa312 100644
--- a/src/mailman/interfaces/messages.py
+++ b/src/mailman/interfaces/messages.py
@@ -18,7 +18,7 @@
 """The message storage service."""
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/mime.py b/src/mailman/interfaces/mime.py
index e30354cd9..c1a6e050f 100644
--- a/src/mailman/interfaces/mime.py
+++ b/src/mailman/interfaces/mime.py
@@ -19,7 +19,7 @@
 
 from enum import Enum
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/mlistrequest.py b/src/mailman/interfaces/mlistrequest.py
index 731caf147..45712ed86 100644
--- a/src/mailman/interfaces/mlistrequest.py
+++ b/src/mailman/interfaces/mlistrequest.py
@@ -18,7 +18,7 @@
 """Interface for a web request accessing a mailing list."""
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/pending.py b/src/mailman/interfaces/pending.py
index b7621cbe2..cf92fed9e 100644
--- a/src/mailman/interfaces/pending.py
+++ b/src/mailman/interfaces/pending.py
@@ -23,7 +23,7 @@ confirmation.
 """
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/pipeline.py b/src/mailman/interfaces/pipeline.py
index 5e39c2a3e..cdef6a768 100644
--- a/src/mailman/interfaces/pipeline.py
+++ b/src/mailman/interfaces/pipeline.py
@@ -18,7 +18,7 @@
 """Interface for describing pipelines."""
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 # For i18n extraction.
diff --git a/src/mailman/interfaces/preferences.py b/src/mailman/interfaces/preferences.py
index b3690ac35..4b5b490cb 100644
--- a/src/mailman/interfaces/preferences.py
+++ b/src/mailman/interfaces/preferences.py
@@ -18,7 +18,7 @@
 """Interface for preferences."""
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/requests.py b/src/mailman/interfaces/requests.py
index be164183e..3098772a9 100644
--- a/src/mailman/interfaces/requests.py
+++ b/src/mailman/interfaces/requests.py
@@ -23,7 +23,7 @@ moderators, such as subscription requests and held messages.
 
 from enum import Enum
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/roster.py b/src/mailman/interfaces/roster.py
index 5ad36847b..2993e4fc4 100644
--- a/src/mailman/interfaces/roster.py
+++ b/src/mailman/interfaces/roster.py
@@ -18,7 +18,7 @@
 """Interface for a roster of members."""
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/rules.py b/src/mailman/interfaces/rules.py
index 7093da5a7..9f5f1365e 100644
--- a/src/mailman/interfaces/rules.py
+++ b/src/mailman/interfaces/rules.py
@@ -18,7 +18,7 @@
 """Interface describing the basics of rules."""
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/runner.py b/src/mailman/interfaces/runner.py
index aed8edddf..e39efb097 100644
--- a/src/mailman/interfaces/runner.py
+++ b/src/mailman/interfaces/runner.py
@@ -18,7 +18,7 @@
 """Interface for runners."""
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/styles.py b/src/mailman/interfaces/styles.py
index 5629af5d4..a183933f7 100644
--- a/src/mailman/interfaces/styles.py
+++ b/src/mailman/interfaces/styles.py
@@ -19,7 +19,7 @@
 
 from mailman import public
 from mailman.interfaces.errors import MailmanError
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/switchboard.py b/src/mailman/interfaces/switchboard.py
index 30dd62843..4428f4b12 100644
--- a/src/mailman/interfaces/switchboard.py
+++ b/src/mailman/interfaces/switchboard.py
@@ -18,7 +18,7 @@
 """Interface for switchboards."""
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/system.py b/src/mailman/interfaces/system.py
index 95e92b20c..1b0a9a2de 100644
--- a/src/mailman/interfaces/system.py
+++ b/src/mailman/interfaces/system.py
@@ -18,7 +18,7 @@
 """System information."""
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/user.py b/src/mailman/interfaces/user.py
index f80b51583..f1932fd7f 100644
--- a/src/mailman/interfaces/user.py
+++ b/src/mailman/interfaces/user.py
@@ -19,7 +19,7 @@
 
 from mailman import public
 from mailman.interfaces.address import AddressError
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/interfaces/usermanager.py b/src/mailman/interfaces/usermanager.py
index 3cd18bd20..87d4bf6e2 100644
--- a/src/mailman/interfaces/usermanager.py
+++ b/src/mailman/interfaces/usermanager.py
@@ -18,7 +18,7 @@
 """Interface describing the user management service."""
 
 from mailman import public
-from zope.interface import Interface, Attribute
+from zope.interface import Attribute, Interface
 
 
 @public
diff --git a/src/mailman/model/domain.py b/src/mailman/model/domain.py
index 8607f0d94..e137da310 100644
--- a/src/mailman/model/domain.py
+++ b/src/mailman/model/domain.py
@@ -26,9 +26,9 @@ from mailman.interfaces.domain import (
 from mailman.interfaces.user import IUser
 from mailman.interfaces.usermanager import IUserManager
 from mailman.model.mailinglist import MailingList
-from urllib.parse import urljoin, urlparse
 from sqlalchemy import Column, Integer, Unicode
 from sqlalchemy.orm import relationship
+from urllib.parse import urljoin, urlparse
 from zope.event import notify
 from zope.interface import implementer
 from zope.component import getUtility
diff --git a/src/mailman/model/subscriptions.py b/src/mailman/model/subscriptions.py
index 1591a3adf..3d2bcbeb0 100644
--- a/src/mailman/model/subscriptions.py
+++ b/src/mailman/model/subscriptions.py
@@ -29,7 +29,7 @@ from mailman.model.member import Member
 from mailman.model.user import User
 from mailman.utilities.queries import QuerySequence
 from operator import attrgetter
-from sqlalchemy.orm.exc import NoResultFound, MultipleResultsFound
+from sqlalchemy.orm.exc import MultipleResultsFound, NoResultFound
 from zope.component import getUtility
 from zope.interface import implementer
 
diff --git a/src/mailman/model/tests/test_listmanager.py b/src/mailman/model/tests/test_listmanager.py
index 464ebfc52..a8ac68c92 100644
--- a/src/mailman/model/tests/test_listmanager.py
+++ b/src/mailman/model/tests/test_listmanager.py
@@ -22,8 +22,8 @@ import unittest
 from mailman.app.lifecycle import create_list
 from mailman.app.moderator import hold_message
 from mailman.config import config
-from mailman.interfaces.autorespond import IAutoResponseSet, Response
 from mailman.interfaces.address import InvalidEmailAddressError
+from mailman.interfaces.autorespond import IAutoResponseSet, Response
 from mailman.interfaces.listmanager import (
     IListManager, ListAlreadyExistsError, ListCreatedEvent, ListCreatingEvent,
     ListDeletedEvent, ListDeletingEvent)
diff --git a/src/mailman/rest/lists.py b/src/mailman/rest/lists.py
index 2d669a267..7315d805a 100644
--- a/src/mailman/rest/lists.py
+++ b/src/mailman/rest/lists.py
@@ -31,11 +31,11 @@ from mailman.interfaces.member import MemberRole
 from mailman.interfaces.styles import IStyleManager
 from mailman.interfaces.subscriptions import ISubscriptionService
 from mailman.rest.bans import BannedEmails
-from mailman.rest.listconf import ListConfiguration
 from mailman.rest.header_matches import HeaderMatches
 from mailman.rest.helpers import (
     CollectionMixin, GetterSetter, NotFound, accepted, bad_request, child,
     created, etag, no_content, not_found, okay)
+from mailman.rest.listconf import ListConfiguration
 from mailman.rest.members import AMember, MemberCollection
 from mailman.rest.post_moderation import HeldMessages
 from mailman.rest.sub_moderation import SubscriptionRequests
diff --git a/src/mailman/rest/queues.py b/src/mailman/rest/queues.py
index 69f6df973..9fa5b9dc6 100644
--- a/src/mailman/rest/queues.py
+++ b/src/mailman/rest/queues.py
@@ -18,8 +18,8 @@
 """<api>/queues."""
 
 from mailman import public
-from mailman.config import config
 from mailman.app.inject import inject_text
+from mailman.config import config
 from mailman.interfaces.listmanager import IListManager
 from mailman.rest.helpers import (
     CollectionMixin, bad_request, created, etag, no_content, not_found, okay)
diff --git a/src/mailman/rest/tests/test_bans.py b/src/mailman/rest/tests/test_bans.py
index e6159d9a4..fc096fa1b 100644
--- a/src/mailman/rest/tests/test_bans.py
+++ b/src/mailman/rest/tests/test_bans.py
@@ -22,8 +22,8 @@ import unittest
 from mailman.app.lifecycle import create_list
 from mailman.database.transaction import transaction
 from mailman.interfaces.bans import IBanManager
-from mailman.testing.layers import RESTLayer
 from mailman.testing.helpers import call_api
+from mailman.testing.layers import RESTLayer
 from urllib.error import HTTPError
 
 
diff --git a/src/mailman/rest/tests/test_membership.py b/src/mailman/rest/tests/test_membership.py
index 3d47b13a7..1ea70e90b 100644
--- a/src/mailman/rest/tests/test_membership.py
+++ b/src/mailman/rest/tests/test_membership.py
@@ -28,10 +28,10 @@ from mailman.interfaces.member import DeliveryMode, MemberRole
 from mailman.interfaces.registrar import IRegistrar
 from mailman.interfaces.subscriptions import TokenOwner
 from mailman.interfaces.usermanager import IUserManager
+from mailman.runners.incoming import IncomingRunner
 from mailman.testing.helpers import (
     TestableMaster, call_api, get_lmtp_client, make_testable_runner,
     set_preferred, subscribe, wait_for_webservice)
-from mailman.runners.incoming import IncomingRunner
 from mailman.testing.layers import ConfigLayer, RESTLayer
 from mailman.utilities.datetime import now
 from urllib.error import HTTPError
diff --git a/src/mailman/rest/tests/test_users.py b/src/mailman/rest/tests/test_users.py
index e42bdf623..890f1df3f 100644
--- a/src/mailman/rest/tests/test_users.py
+++ b/src/mailman/rest/tests/test_users.py
@@ -25,11 +25,11 @@ from mailman.config import config
 from mailman.database.transaction import transaction
 from mailman.interfaces.member import DeliveryMode
 from mailman.interfaces.usermanager import IUserManager
+from mailman.model.preferences import Preferences
 from mailman.testing.helpers import call_api, configuration
 from mailman.testing.layers import RESTLayer
 from urllib.error import HTTPError
 from zope.component import getUtility
-from mailman.model.preferences import Preferences
 
 
 class TestUsers(unittest.TestCase):
diff --git a/src/mailman/rest/tests/test_validator.py b/src/mailman/rest/tests/test_validator.py
index de2207108..5da4349d2 100644
--- a/src/mailman/rest/tests/test_validator.py
+++ b/src/mailman/rest/tests/test_validator.py
@@ -19,8 +19,8 @@
 
 import unittest
 
-from mailman.interfaces.usermanager import IUserManager
 from mailman.core.api import API30, API31
+from mailman.interfaces.usermanager import IUserManager
 from mailman.rest.validator import (
     list_of_strings_validator, subscriber_validator)
 from mailman.testing.layers import RESTLayer
diff --git a/src/mailman/rest/wsgiapp.py b/src/mailman/rest/wsgiapp.py
index 6184da4ee..2c22948bb 100644
--- a/src/mailman/rest/wsgiapp.py
+++ b/src/mailman/rest/wsgiapp.py
@@ -27,8 +27,8 @@ from mailman import public
 from mailman.config import config
 from mailman.database.transaction import transactional
 from mailman.rest.root import Root
-from wsgiref.simple_server import WSGIRequestHandler, WSGIServer
-from wsgiref.simple_server import make_server as wsgi_server
+from wsgiref.simple_server import (
+    WSGIRequestHandler, WSGIServer, make_server as wsgi_server)
 
 
 log = logging.getLogger('mailman.http')
diff --git a/src/mailman/runners/archive.py b/src/mailman/runners/archive.py
index cfa0b1a12..7bf655a24 100644
--- a/src/mailman/runners/archive.py
+++ b/src/mailman/runners/archive.py
@@ -20,15 +20,15 @@
 import copy
 import logging
 
-from email.utils import parsedate_tz, mktime_tz
 from datetime import datetime
+from email.utils import parsedate_tz, mktime_tz
 from lazr.config import as_timedelta
 from mailman import public
 from mailman.config import config
 from mailman.core.runner import Runner
 from mailman.interfaces.archiver import ClobberDate
-from mailman.utilities.datetime import RFC822_DATE_FMT, now
 from mailman.interfaces.mailinglist import IListArchiverSet
+from mailman.utilities.datetime import RFC822_DATE_FMT, now
 
 
 log = logging.getLogger('mailman.archiver')
diff --git a/src/mailman/runners/tests/test_lmtp.py b/src/mailman/runners/tests/test_lmtp.py
index 9d86af2dc..b4f810947 100644
--- a/src/mailman/runners/tests/test_lmtp.py
+++ b/src/mailman/runners/tests/test_lmtp.py
@@ -22,8 +22,8 @@ import smtplib
 import unittest
 
 from datetime import datetime
-from mailman.config import config
 from mailman.app.lifecycle import create_list
+from mailman.config import config
 from mailman.database.transaction import transaction
 from mailman.testing.helpers import get_lmtp_client, get_queue_messages
 from mailman.testing.layers import LMTPLayer
diff --git a/src/mailman/runners/tests/test_owner.py b/src/mailman/runners/tests/test_owner.py
index 48ccaaba0..1aa430b28 100644
--- a/src/mailman/runners/tests/test_owner.py
+++ b/src/mailman/runners/tests/test_owner.py
@@ -29,11 +29,11 @@ from mailman.config import config
 from mailman.database.transaction import transaction
 from mailman.interfaces.member import MemberRole
 from mailman.interfaces.usermanager import IUserManager
-from mailman.testing.helpers import (
-    TestableMaster, get_lmtp_client, make_testable_runner)
 from mailman.runners.incoming import IncomingRunner
 from mailman.runners.outgoing import OutgoingRunner
 from mailman.runners.pipeline import PipelineRunner
+from mailman.testing.helpers import (
+    TestableMaster, get_lmtp_client, make_testable_runner)
 from mailman.testing.layers import SMTPLayer
 from operator import itemgetter
 from zope.component import getUtility
diff --git a/src/mailman/testing/flake8.py b/src/mailman/testing/flake8.py
index d002e8b6c..df4e39c90 100644
--- a/src/mailman/testing/flake8.py
+++ b/src/mailman/testing/flake8.py
@@ -19,17 +19,39 @@
 
 
 from ast import NodeVisitor
+from collections import namedtuple
+from enum import Enum
+
+
+class ImportType(Enum):
+    non_from = 0
+    from_import = 1
+
+
+ImportRecord = namedtuple('ImportRecord', 'itype lineno colno, module, names')
 
 
 class ImportVisitor(NodeVisitor):
     def __init__(self):
-        self.last_import = None
+        self.imports = []
 
     def visit_Import(self, node):
         if node.col_offset != 0:
             # Ignore nested imports.
             return
-        
+        names = [alias.name for alias in node.names]
+        self.imports.append(
+            ImportRecord(ImportType.non_from, node.lineno, node.col_offset,
+                         None, names))
+
+    def visit_ImportFrom(self, node):
+        if node.col_offset != 0:
+            # Ignore nested imports.
+            return
+        names = [alias.name for alias in node.names]
+        self.imports.append(
+            ImportRecord(ImportType.from_import, node.lineno, node.col_offset,
+                         node.module, names))
 
 
 class ImportOrder:
@@ -40,5 +62,65 @@ class ImportOrder:
         self.tree = tree
         self.filename = filename
 
+    def _error(self, record, code, text):
+        return (record.lineno, record.colno,
+                '{} {}'.format(code, text), ImportOrder)
+
     def run(self):
-        print('Running', self.name, self.version)
+        visitor = ImportVisitor()
+        visitor.visit(self.tree)
+        last_import = None
+        for record in visitor.imports:
+            if last_import is None:
+                last_import = record
+                continue
+            if record.itype is ImportType.non_from:
+                if len(record.names) != 1:
+                    yield self._error(record, 'B402',
+                                      'Multiple names on non-from import')
+                if last_import.itype is ImportType.from_import:
+                    yield self._error(record, 'B401',
+                                      'Non-from import follows from-import')
+                if len(last_import.names[0]) > len(record.names[0]):
+                    yield self._error(
+                        record, 'B403',
+                        'Shorter non-from import follows longer')
+                # It's also possible that the imports are the same length, in
+                # which case they must be sorted alphabetically.
+                if (len(last_import.names[0]) == len(record.names[0]) and
+                        last_import.names[0] > record.names[0]):
+                    yield self._error(
+                        record, 'B404',
+                        'Non-from imports not alphabetically sorted')
+                if last_import.lineno + 1 != record.lineno:
+                    yield self._error(
+                        record, 'B405',
+                        'Unexpected blank line since last non-from import')
+            else:
+                assert record.itype is ImportType.from_import
+                if (last_import.itype is ImportType.non_from and
+                        record.lineno != last_import.lineno + 2):
+                    yield self._error(
+                        record, 'B406',
+                        'Expected one blank line since last non-from import')
+                if last_import.itype is ImportType.non_from:
+                    last_import = record
+                    continue
+                if last_import.module > record.module:
+                    yield self._error(
+                        record, 'B407',
+                        'From-imports not sorted alphabetically')
+                # All imports from the same module should show up in the same
+                # multiline import.
+                if last_import.module == record.module:
+                    yield self._error(
+                        record, 'B408',
+                        'Importing from same module on different lines')
+                # Check the sort order of the imported names.
+                if sorted(record.names) != record.names:
+                    yield self._error(
+                        record, 'B409',
+                        'Imported names are not sorted alphabetically')
+                # How to check for no blank lines between from imports?
+            # Update the last import.
+            last_import = record
diff --git a/src/mailman/utilities/importer.py b/src/mailman/utilities/importer.py
index acd673c7d..9a5684d9c 100644
--- a/src/mailman/utilities/importer.py
+++ b/src/mailman/utilities/importer.py
@@ -37,9 +37,8 @@ from mailman.interfaces.digests import DigestFrequency
 from mailman.interfaces.errors import MailmanError
 from mailman.interfaces.languages import ILanguageManager
 from mailman.interfaces.mailinglist import (
-    IAcceptableAliasSet, IHeaderMatchList)
-from mailman.interfaces.mailinglist import Personalization, ReplyToMunging
-from mailman.interfaces.mailinglist import SubscriptionPolicy
+    IAcceptableAliasSet, IHeaderMatchList, Personalization, ReplyToMunging,
+    SubscriptionPolicy)
 from mailman.interfaces.member import DeliveryMode, DeliveryStatus, MemberRole
 from mailman.interfaces.nntp import NewsgroupModeration
 from mailman.interfaces.usermanager import IUserManager