44 files changed, 87 insertions, 110 deletions

diff --git a/src/mailman/app/notifications.py b/src/mailman/app/notifications.py
index 1e8f1b820..fc8a0549e 100644
--- a/src/mailman/app/notifications.py
+++ b/src/mailman/app/notifications.py
@@ -35,7 +35,7 @@ from mailman.interfaces.member import DeliveryMode
 from mailman.interfaces.templates import ITemplateLoader
 from mailman.utilities.i18n import make
 from mailman.utilities.string import expand, wrap
-from six.moves.urllib_error import URLError
+from urllib.error import URLError
 from zope.component import getUtility
 
 
diff --git a/src/mailman/app/templates.py b/src/mailman/app/templates.py
index 4c4684523..86c61d046 100644
--- a/src/mailman/app/templates.py
+++ b/src/mailman/app/templates.py
@@ -27,11 +27,10 @@ from mailman.interfaces.languages import ILanguageManager
 from mailman.interfaces.listmanager import IListManager
 from mailman.interfaces.templates import ITemplateLoader
 from mailman.utilities.i18n import TemplateNotFoundError, find
-from six.moves.urllib_error import URLError
-from six.moves.urllib_parse import urlparse
-from six.moves.urllib_request import (
-    BaseHandler, build_opener, install_opener, urlopen)
-from six.moves.urllib_response import addinfourl
+from urllib.error import URLError
+from urllib.parse import urlparse
+from urllib.request import BaseHandler, build_opener, install_opener, urlopen
+from urllib.response import addinfourl
 from zope.component import getUtility
 from zope.interface import implementer
 
diff --git a/src/mailman/app/tests/test_templates.py b/src/mailman/app/tests/test_templates.py
index 880e3da90..7aab8f1f9 100644
--- a/src/mailman/app/tests/test_templates.py
+++ b/src/mailman/app/tests/test_templates.py
@@ -23,7 +23,6 @@ __all__ = [
 
 
 import os
-import six
 import shutil
 import tempfile
 import unittest
@@ -33,7 +32,7 @@ from mailman.config import config
 from mailman.interfaces.languages import ILanguageManager
 from mailman.interfaces.templates import ITemplateLoader
 from mailman.testing.layers import ConfigLayer
-from six.moves.urllib_error import URLError
+from urllib.error import URLError
 from zope.component import getUtility
 
 
@@ -132,5 +131,5 @@ class TestTemplateLoader(unittest.TestCase):
         with open(os.path.join(path, 'demo.txt'), 'wb') as fp:
             fp.write(test_text)
         content = self._loader.get('mailman:///it/demo.txt')
-        self.assertIsInstance(content, six.text_type)
+        self.assertIsInstance(content, str)
         self.assertEqual(content, test_text.decode('utf-8'))
diff --git a/src/mailman/archiving/mailarchive.py b/src/mailman/archiving/mailarchive.py
index 4ede57856..b7f3847f0 100644
--- a/src/mailman/archiving/mailarchive.py
+++ b/src/mailman/archiving/mailarchive.py
@@ -25,7 +25,7 @@ __all__ = [
 from mailman.config import config
 from mailman.config.config import external_configuration
 from mailman.interfaces.archiver import ArchivePolicy, IArchiver
-from six.moves.urllib_parse import quote, urljoin
+from urllib.parse import quote, urljoin
 from zope.interface import implementer
 
 
diff --git a/src/mailman/archiving/mhonarc.py b/src/mailman/archiving/mhonarc.py
index bdba612f3..ff8baf079 100644
--- a/src/mailman/archiving/mhonarc.py
+++ b/src/mailman/archiving/mhonarc.py
@@ -29,7 +29,7 @@ from mailman.config import config
 from mailman.config.config import external_configuration
 from mailman.interfaces.archiver import IArchiver
 from mailman.utilities.string import expand
-from six.moves.urllib_parse import urljoin
+from urllib.parse import urljoin
 from zope.interface import implementer
 
 
diff --git a/src/mailman/archiving/prototype.py b/src/mailman/archiving/prototype.py
index 41b413105..b0328211e 100644
--- a/src/mailman/archiving/prototype.py
+++ b/src/mailman/archiving/prototype.py
@@ -31,7 +31,7 @@ from flufl.lock import Lock, TimeOutError
 from mailbox import Maildir
 from mailman.config import config
 from mailman.interfaces.archiver import IArchiver
-from six.moves.urllib_parse import urljoin
+from urllib.parse import urljoin
 from zope.interface import implementer
 
 
diff --git a/src/mailman/commands/cli_import.py b/src/mailman/commands/cli_import.py
index b91a288ea..30aeb7894 100644
--- a/src/mailman/commands/cli_import.py
+++ b/src/mailman/commands/cli_import.py
@@ -23,13 +23,13 @@ __all__ = [
 
 
 import sys
+import pickle
 
 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 six.moves import cPickle
 from zope.component import getUtility
 from zope.interface import implementer
 
@@ -77,10 +77,10 @@ class Import21:
         with open(filename, 'rb') as fp:
             while True:
                 try:
-                    config_dict = cPickle.load(fp)
+                    config_dict = pickle.load(fp)
                 except EOFError:
                     break
-                except cPickle.UnpicklingError:
+                except pickle.UnpicklingError:
                     self.parser.error(
                         _('Not a Mailman 2.1 configuration file: $filename'))
                     return
diff --git a/src/mailman/commands/cli_qfile.py b/src/mailman/commands/cli_qfile.py
index 3ce007dad..55669e981 100644
--- a/src/mailman/commands/cli_qfile.py
+++ b/src/mailman/commands/cli_qfile.py
@@ -22,13 +22,12 @@ __all__ = [
     ]
 
 
-import six
+import pickle
 
 from mailman.core.i18n import _
 from mailman.interfaces.command import ICLISubCommand
 from mailman.utilities.interact import interact
 from pprint import PrettyPrinter
-from six.moves import cPickle
 from zope.interface import implementer
 
 
@@ -72,7 +71,7 @@ class QFile:
         with open(args.qfile[0], 'rb') as fp:
             while True:
                 try:
-                    m.append(cPickle.load(fp))
+                    m.append(pickle.load(fp))
                 except EOFError:
                     break
         if args.doprint:
@@ -80,7 +79,7 @@ class QFile:
             for i, obj in enumerate(m):
                 count = i + 1
                 print(_('<----- start object $count ----->'))
-                if isinstance(obj, six.string_types):
+                if isinstance(obj, (bytes, str)):
                     print(obj)
                 else:
                     printer.pprint(obj)
diff --git a/src/mailman/commands/docs/inject.rst b/src/mailman/commands/docs/inject.rst
index de295b8f6..68a5d534d 100644
--- a/src/mailman/commands/docs/inject.rst
+++ b/src/mailman/commands/docs/inject.rst
@@ -133,9 +133,8 @@ Standard input
 The message text can also be provided on standard input.
 ::
 
-    >>> from six import StringIO
+    >>> from io import StringIO
 
-    # Remember: we've got unicode literals turned on.
     >>> standard_in = StringIO(str("""\
     ... From: bperson@example.com
     ... To: test@example.com
diff --git a/src/mailman/commands/docs/members.rst b/src/mailman/commands/docs/members.rst
index 28f238f31..490287235 100644
--- a/src/mailman/commands/docs/members.rst
+++ b/src/mailman/commands/docs/members.rst
@@ -229,7 +229,7 @@ You can also specify ``-`` as the filename, in which case the addresses are
 taken from standard input.
 ::
 
-    >>> from six import StringIO
+    >>> from io import StringIO
     >>> fp = StringIO()
     >>> for address in ('dperson@example.com',
     ...                 'Elly Person <eperson@example.com>',
diff --git a/src/mailman/commands/tests/test_conf.py b/src/mailman/commands/tests/test_conf.py
index 972148cc2..5ff93895d 100644
--- a/src/mailman/commands/tests/test_conf.py
+++ b/src/mailman/commands/tests/test_conf.py
@@ -28,9 +28,9 @@ import mock
 import tempfile
 import unittest
 
+from io import StringIO
 from mailman.commands.cli_conf import Conf
 from mailman.testing.layers import ConfigLayer
-from six import StringIO
 
 
 
diff --git a/src/mailman/config/config.py b/src/mailman/config/config.py
index 6e518dea0..ada4c6bac 100644
--- a/src/mailman/config/config.py
+++ b/src/mailman/config/config.py
@@ -28,6 +28,7 @@ import os
 import sys
 import mailman.templates
 
+from configparser import ConfigParser, RawConfigParser
 from flufl.lock import Lock
 from lazr.config import ConfigSchema, as_boolean
 from mailman import version
@@ -37,7 +38,6 @@ from mailman.interfaces.languages import ILanguageManager
 from mailman.utilities.filesystem import makedirs
 from mailman.utilities.modules import call_name, expand_path
 from pkg_resources import resource_filename, resource_string as resource_bytes
-from six.moves.configparser import ConfigParser, RawConfigParser
 from string import Template
 from unittest.mock import patch
 from zope.component import getUtility
diff --git a/src/mailman/core/runner.py b/src/mailman/core/runner.py
index f198a4641..75dc644b3 100644
--- a/src/mailman/core/runner.py
+++ b/src/mailman/core/runner.py
@@ -27,6 +27,7 @@ import signal
 import logging
 import traceback
 
+from io import StringIO
 from lazr.config import as_boolean, as_timedelta
 from mailman.config import config
 from mailman.core.i18n import _
@@ -36,7 +37,6 @@ from mailman.interfaces.languages import ILanguageManager
 from mailman.interfaces.listmanager import IListManager
 from mailman.interfaces.runner import IRunner, RunnerCrashEvent
 from mailman.utilities.string import expand
-from six.moves import cStringIO as StringIO
 from zope.component import getUtility
 from zope.event import notify
 from zope.interface import implementer
diff --git a/src/mailman/core/switchboard.py b/src/mailman/core/switchboard.py
index 15ad06416..402770cd9 100644
--- a/src/mailman/core/switchboard.py
+++ b/src/mailman/core/switchboard.py
@@ -43,7 +43,6 @@ from mailman.interfaces.configuration import ConfigurationUpdatedEvent
 from mailman.interfaces.switchboard import ISwitchboard
 from mailman.utilities.filesystem import makedirs
 from mailman.utilities.string import expand
-from six.moves import cPickle
 from zope.interface import implementer
 
 
@@ -114,10 +113,10 @@ class Switchboard:
         now = repr(time.time())
         if data.get('_plaintext'):
             protocol = 0
-            msgsave = cPickle.dumps(str(_msg), protocol)
+            msgsave = pickle.dumps(str(_msg), protocol)
         else:
             protocol = pickle.HIGHEST_PROTOCOL
-            msgsave = cPickle.dumps(_msg, protocol)
+            msgsave = pickle.dumps(_msg, protocol)
         # The list-id field is a string but the input to the hash function must
         # be bytes.
         hashfood = msgsave + list_id.encode('utf-8') + now.encode('utf-8')
@@ -141,7 +140,7 @@ class Switchboard:
         # Write to the pickle file the message object and metadata.
         with open(tmpfile, 'wb') as fp:
             fp.write(msgsave)
-            cPickle.dump(data, fp, protocol)
+            pickle.dump(data, fp, protocol)
             fp.flush()
             os.fsync(fp.fileno())
         os.rename(tmpfile, filename)
@@ -158,8 +157,8 @@ class Switchboard:
             # process crashes uncleanly the .bak file will be used to
             # re-instate the .pck file in order to try again.
             os.rename(filename, backfile)
-            msg = cPickle.load(fp)
-            data = cPickle.load(fp)
+            msg = pickle.load(fp)
+            data = pickle.load(fp)
         if data.get('_parsemsg'):
             # Calculate the original size of the text now so that we won't
             # have to generate the message later when we do size restriction
@@ -226,9 +225,9 @@ class Switchboard:
             with open(src, 'rb+') as fp:
                 try:
                     # Throw away the message object.
-                    cPickle.load(fp)
+                    pickle.load(fp)
                     data_pos = fp.tell()
-                    data = cPickle.load(fp)
+                    data = pickle.load(fp)
                 except Exception as error:
                     # If unpickling throws any exception, just log and
                     # preserve this entry
@@ -242,7 +241,7 @@ class Switchboard:
                         protocol = 0
                     else:
                         protocol = 1
-                    cPickle.dump(data, fp, protocol)
+                    pickle.dump(data, fp, protocol)
                     fp.truncate()
                     fp.flush()
                     os.fsync(fp.fileno())
diff --git a/src/mailman/database/sqlite.py b/src/mailman/database/sqlite.py
index e6c9857b2..e1c3bf095 100644
--- a/src/mailman/database/sqlite.py
+++ b/src/mailman/database/sqlite.py
@@ -25,7 +25,7 @@ __all__ = [
 import os
 
 from mailman.database.base import SABaseDatabase
-from six.moves.urllib_parse import urlparse
+from urllib.parse import urlparse
 
 
 
diff --git a/src/mailman/handlers/decorate.py b/src/mailman/handlers/decorate.py
index be6620019..7f09c74e4 100644
--- a/src/mailman/handlers/decorate.py
+++ b/src/mailman/handlers/decorate.py
@@ -33,7 +33,7 @@ from mailman.email.message import Message
 from mailman.interfaces.handler import IHandler
 from mailman.interfaces.templates import ITemplateLoader
 from mailman.utilities.string import expand
-from six.moves.urllib_error import URLError
+from urllib.error import URLError
 from zope.component import getUtility
 from zope.interface import implementer
 
diff --git a/src/mailman/model/domain.py b/src/mailman/model/domain.py
index 768075c30..9e627c119 100644
--- a/src/mailman/model/domain.py
+++ b/src/mailman/model/domain.py
@@ -29,7 +29,7 @@ from mailman.interfaces.domain import (
     BadDomainSpecificationError, DomainCreatedEvent, DomainCreatingEvent,
     DomainDeletedEvent, DomainDeletingEvent, IDomain, IDomainManager)
 from mailman.model.mailinglist import MailingList
-from six.moves.urllib_parse import urljoin, urlparse
+from urllib.parse import urljoin, urlparse
 from sqlalchemy import Column, Integer, Unicode
 from zope.event import notify
 from zope.interface import implementer
diff --git a/src/mailman/model/mailinglist.py b/src/mailman/model/mailinglist.py
index 738ce6fbd..a204d54cd 100644
--- a/src/mailman/model/mailinglist.py
+++ b/src/mailman/model/mailinglist.py
@@ -52,12 +52,12 @@ from mailman.model.mime import ContentFilter
 from mailman.model.preferences import Preferences
 from mailman.utilities.filesystem import makedirs
 from mailman.utilities.string import expand
-from six.moves.urllib_parse import urljoin
 from sqlalchemy import (
     Boolean, Column, DateTime, Float, ForeignKey, Integer, Interval,
     LargeBinary, PickleType, Unicode)
 from sqlalchemy.event import listen
 from sqlalchemy.orm import relationship
+from urllib.parse import urljoin
 from zope.component import getUtility
 from zope.event import notify
 from zope.interface import implementer
diff --git a/src/mailman/model/requests.py b/src/mailman/model/requests.py
index de0c51d99..e984d0aea 100644
--- a/src/mailman/model/requests.py
+++ b/src/mailman/model/requests.py
@@ -23,15 +23,13 @@ __all__ = [
     ]
 
 
-import six
-
 from datetime import timedelta
 from mailman.database.model import Model
 from mailman.database.transaction import dbconnection
 from mailman.database.types import Enum
 from mailman.interfaces.pending import IPendable, IPendings
 from mailman.interfaces.requests import IListRequests, RequestType
-from six.moves.cPickle import dumps, loads
+from pickle import dumps, loads
 from sqlalchemy import Column, ForeignKey, Integer, Unicode
 from sqlalchemy.orm import relationship
 from zope.component import getUtility
@@ -50,8 +48,8 @@ class DataPendable(dict):
         # such a way that it will be properly reconstituted when unpended.
         clean_mapping = {}
         for key, value in mapping.items():
-            assert isinstance(key, six.string_types)
-            if not isinstance(value, six.text_type):
+            assert isinstance(key, (bytes, str))
+            if not isinstance(value, str):
                 key = '_pck_' + key
                 value = dumps(value).decode('raw-unicode-escape')
             clean_mapping[key] = value
diff --git a/src/mailman/rest/addresses.py b/src/mailman/rest/addresses.py
index 0d06391ea..2ce456b98 100644
--- a/src/mailman/rest/addresses.py
+++ b/src/mailman/rest/addresses.py
@@ -24,8 +24,6 @@ __all__ = [
     ]
 
 
-import six
-
 from mailman.interfaces.address import (
     ExistingAddressError, InvalidEmailAddressError)
 from mailman.interfaces.usermanager import IUserManager
@@ -196,8 +194,8 @@ class UserAddresses(_AddressBase):
             not_found(response)
             return
         user_manager = getUtility(IUserManager)
-        validator = Validator(email=six.text_type,
-                              display_name=six.text_type,
+        validator = Validator(email=str,
+                              display_name=str,
                               _optional=('display_name',))
         try:
             address = user_manager.create_address(**validator(request))
diff --git a/src/mailman/rest/docs/helpers.rst b/src/mailman/rest/docs/helpers.rst
index 5614e6544..c40619c01 100644
--- a/src/mailman/rest/docs/helpers.rst
+++ b/src/mailman/rest/docs/helpers.rst
@@ -69,9 +69,8 @@ Another helper unpacks ``POST`` and ``PUT`` request variables, validating and
 converting their values.
 ::
 
-    >>> import six
     >>> from mailman.rest.validator import Validator
-    >>> validator = Validator(one=int, two=six.text_type, three=bool)
+    >>> validator = Validator(one=int, two=str, three=bool)
 
     >>> class FakeRequest:
     ...     params = None
@@ -120,7 +119,7 @@ Extra keys are also not allowed.
 However, if optional keys are missing, it's okay.
 ::
 
-    >>> validator = Validator(one=int, two=six.text_type, three=bool,
+    >>> validator = Validator(one=int, two=str, three=bool,
     ...                       four=int, five=int,
     ...                       _optional=('four', 'five'))
 
diff --git a/src/mailman/rest/domains.py b/src/mailman/rest/domains.py
index 02b46494b..345e8327d 100644
--- a/src/mailman/rest/domains.py
+++ b/src/mailman/rest/domains.py
@@ -23,8 +23,6 @@ __all__ = [
     ]
 
 
-import six
-
 from mailman.interfaces.domain import (
     BadDomainSpecificationError, IDomainManager)
 from mailman.rest.helpers import (
@@ -98,10 +96,10 @@ class AllDomains(_DomainBase):
         """Create a new domain."""
         domain_manager = getUtility(IDomainManager)
         try:
-            validator = Validator(mail_host=six.text_type,
-                                  description=six.text_type,
-                                  base_url=six.text_type,
-                                  contact_address=six.text_type,
+            validator = Validator(mail_host=str,
+                                  description=str,
+                                  base_url=str,
+                                  contact_address=str,
                                   _optional=('description', 'base_url',
                                              'contact_address'))
             domain = domain_manager.add(**validator(request))
diff --git a/src/mailman/rest/listconf.py b/src/mailman/rest/listconf.py
index 831d6fefe..e83f52833 100644
--- a/src/mailman/rest/listconf.py
+++ b/src/mailman/rest/listconf.py
@@ -22,8 +22,6 @@ __all__ = [
     ]
 
 
-import six
-
 from lazr.config import as_boolean, as_timedelta
 from mailman.config import config
 from mailman.core.errors import (
@@ -108,9 +106,9 @@ ATTRIBUTES = dict(
     autorespond_postings=GetterSetter(enum_validator(ResponseAction)),
     autorespond_requests=GetterSetter(enum_validator(ResponseAction)),
     autoresponse_grace_period=GetterSetter(as_timedelta),
-    autoresponse_owner_text=GetterSetter(six.text_type),
-    autoresponse_postings_text=GetterSetter(six.text_type),
-    autoresponse_request_text=GetterSetter(six.text_type),
+    autoresponse_owner_text=GetterSetter(str),
+    autoresponse_postings_text=GetterSetter(str),
+    autoresponse_request_text=GetterSetter(str),
     archive_policy=GetterSetter(enum_validator(ArchivePolicy)),
     bounces_address=GetterSetter(None),
     collapse_alternatives=GetterSetter(as_boolean),
@@ -118,7 +116,7 @@ ATTRIBUTES = dict(
     created_at=GetterSetter(None),
     default_member_action=GetterSetter(enum_validator(Action)),
     default_nonmember_action=GetterSetter(enum_validator(Action)),
-    description=GetterSetter(six.text_type),
+    description=GetterSetter(str),
     digest_last_sent_at=GetterSetter(None),
     digest_size_threshold=GetterSetter(float),
     filter_content=GetterSetter(as_boolean),
@@ -137,16 +135,16 @@ ATTRIBUTES = dict(
     post_id=GetterSetter(None),
     posting_address=GetterSetter(None),
     posting_pipeline=GetterSetter(pipeline_validator),
-    display_name=GetterSetter(six.text_type),
+    display_name=GetterSetter(str),
     reply_goes_to_list=GetterSetter(enum_validator(ReplyToMunging)),
-    reply_to_address=GetterSetter(six.text_type),
+    reply_to_address=GetterSetter(str),
     request_address=GetterSetter(None),
     scheme=GetterSetter(None),
     send_welcome_message=GetterSetter(as_boolean),
-    subject_prefix=GetterSetter(six.text_type),
+    subject_prefix=GetterSetter(str),
     volume=GetterSetter(None),
     web_host=GetterSetter(None),
-    welcome_message_uri=GetterSetter(six.text_type),
+    welcome_message_uri=GetterSetter(str),
     )
 
 
diff --git a/src/mailman/rest/lists.py b/src/mailman/rest/lists.py
index c6233796b..f6bc27917 100644
--- a/src/mailman/rest/lists.py
+++ b/src/mailman/rest/lists.py
@@ -27,8 +27,6 @@ __all__ = [
     ]
 
 
-import six
-
 from lazr.config import as_boolean
 from mailman.app.lifecycle import create_list, remove_list
 from mailman.config import config
@@ -202,8 +200,8 @@ class AllLists(_ListBase):
     def on_post(self, request, response):
         """Create a new mailing list."""
         try:
-            validator = Validator(fqdn_listname=six.text_type,
-                                  style_name=six.text_type,
+            validator = Validator(fqdn_listname=str,
+                                  style_name=str,
                                   _optional=('style_name',))
             mlist = create_list(**validator(request))
         except ListAlreadyExistsError:
diff --git a/src/mailman/rest/members.py b/src/mailman/rest/members.py
index 5451f7f76..925cd6718 100644
--- a/src/mailman/rest/members.py
+++ b/src/mailman/rest/members.py
@@ -25,8 +25,6 @@ __all__ = [
     ]
 
 
-import six
-
 from mailman.app.membership import delete_member
 from mailman.interfaces.address import InvalidEmailAddressError
 from mailman.interfaces.listmanager import IListManager, NoSuchListError
@@ -174,7 +172,7 @@ class AMember(_MemberBase):
             return
         try:
             values = Validator(
-                address=six.text_type,
+                address=str,
                 delivery_mode=enum_validator(DeliveryMode),
                 _optional=('address', 'delivery_mode'))(request)
         except ValueError as error:
@@ -205,9 +203,9 @@ class AllMembers(_MemberBase):
         service = getUtility(ISubscriptionService)
         try:
             validator = Validator(
-                list_id=six.text_type,
+                list_id=str,
                 subscriber=subscriber_validator,
-                display_name=six.text_type,
+                display_name=str,
                 delivery_mode=enum_validator(DeliveryMode),
                 role=enum_validator(MemberRole),
                 _optional=('delivery_mode', 'display_name', 'role'))
@@ -254,8 +252,8 @@ class FindMembers(_MemberBase):
         """Find a member"""
         service = getUtility(ISubscriptionService)
         validator = Validator(
-            list_id=six.text_type,
-            subscriber=six.text_type,
+            list_id=str,
+            subscriber=str,
             role=enum_validator(MemberRole),
             _optional=('list_id', 'subscriber', 'role'))
         try:
diff --git a/src/mailman/rest/queues.py b/src/mailman/rest/queues.py
index f1007052e..190f9091e 100644
--- a/src/mailman/rest/queues.py
+++ b/src/mailman/rest/queues.py
@@ -24,8 +24,6 @@ __all__ = [
     ]
 
 
-import six
-
 from mailman.config import config
 from mailman.app.inject import inject_text
 from mailman.interfaces.listmanager import IListManager
@@ -75,8 +73,8 @@ class AQueue(_QueuesBase):
     def on_post(self, request, response):
         """Inject a message into the queue."""
         try:
-            validator = Validator(list_id=six.text_type,
-                                  text=six.text_type)
+            validator = Validator(list_id=str,
+                                  text=str)
             values = validator(request)
         except ValueError as error:
             bad_request(response, str(error))
diff --git a/src/mailman/rest/tests/test_addresses.py b/src/mailman/rest/tests/test_addresses.py
index d08152333..584b81695 100644
--- a/src/mailman/rest/tests/test_addresses.py
+++ b/src/mailman/rest/tests/test_addresses.py
@@ -30,7 +30,7 @@ from mailman.interfaces.usermanager import IUserManager
 from mailman.testing.helpers import call_api
 from mailman.testing.layers import RESTLayer
 from mailman.utilities.datetime import now
-from six.moves.urllib_error import HTTPError
+from urllib.error import HTTPError
 from zope.component import getUtility
 
 
diff --git a/src/mailman/rest/tests/test_domains.py b/src/mailman/rest/tests/test_domains.py
index d10af30ef..bf53c8e70 100644
--- a/src/mailman/rest/tests/test_domains.py
+++ b/src/mailman/rest/tests/test_domains.py
@@ -29,7 +29,7 @@ from mailman.database.transaction import transaction
 from mailman.interfaces.listmanager import IListManager
 from mailman.testing.helpers import call_api
 from mailman.testing.layers import RESTLayer
-from six.moves.urllib_error import HTTPError
+from urllib.error import HTTPError
 from zope.component import getUtility
 
 
diff --git a/src/mailman/rest/tests/test_lists.py b/src/mailman/rest/tests/test_lists.py
index fed9865c4..a365db969 100644
--- a/src/mailman/rest/tests/test_lists.py
+++ b/src/mailman/rest/tests/test_lists.py
@@ -32,7 +32,7 @@ from mailman.database.transaction import transaction
 from mailman.interfaces.usermanager import IUserManager
 from mailman.testing.helpers import call_api
 from mailman.testing.layers import RESTLayer
-from six.moves.urllib_error import HTTPError
+from urllib.error import HTTPError
 from zope.component import getUtility
 
 
diff --git a/src/mailman/rest/tests/test_membership.py b/src/mailman/rest/tests/test_membership.py
index 2841f6634..e1bff833b 100644
--- a/src/mailman/rest/tests/test_membership.py
+++ b/src/mailman/rest/tests/test_membership.py
@@ -35,7 +35,7 @@ from mailman.testing.helpers import (
 from mailman.runners.incoming import IncomingRunner
 from mailman.testing.layers import ConfigLayer, RESTLayer
 from mailman.utilities.datetime import now
-from six.moves.urllib_error import HTTPError
+from urllib.error import HTTPError
 from zope.component import getUtility
 
 
diff --git a/src/mailman/rest/tests/test_moderation.py b/src/mailman/rest/tests/test_moderation.py
index 83261e8e4..262a7ec60 100644
--- a/src/mailman/rest/tests/test_moderation.py
+++ b/src/mailman/rest/tests/test_moderation.py
@@ -32,7 +32,7 @@ from mailman.interfaces.member import DeliveryMode
 from mailman.testing.helpers import (
     call_api, specialized_message_from_string as mfs)
 from mailman.testing.layers import RESTLayer
-from six.moves.urllib_error import HTTPError
+from urllib.error import HTTPError
 
 
 
diff --git a/src/mailman/rest/tests/test_preferences.py b/src/mailman/rest/tests/test_preferences.py
index 1caf61d61..909b1e0e3 100644
--- a/src/mailman/rest/tests/test_preferences.py
+++ b/src/mailman/rest/tests/test_preferences.py
@@ -29,7 +29,7 @@ from mailman.database.transaction import transaction
 from mailman.interfaces.usermanager import IUserManager
 from mailman.testing.helpers import call_api
 from mailman.testing.layers import RESTLayer
-from six.moves.urllib_error import HTTPError
+from urllib.error import HTTPError
 from zope.component import getUtility
 
 
diff --git a/src/mailman/rest/tests/test_queues.py b/src/mailman/rest/tests/test_queues.py
index 43659a2e4..cc860112b 100644
--- a/src/mailman/rest/tests/test_queues.py
+++ b/src/mailman/rest/tests/test_queues.py
@@ -29,7 +29,7 @@ from mailman.config import config
 from mailman.database.transaction import transaction
 from mailman.testing.helpers import call_api, get_queue_messages
 from mailman.testing.layers import RESTLayer
-from six.moves.urllib_error import HTTPError
+from urllib.error import HTTPError
 
 
 TEXT = """\
diff --git a/src/mailman/rest/tests/test_root.py b/src/mailman/rest/tests/test_root.py
index 75e53dd8c..6d10fc635 100644
--- a/src/mailman/rest/tests/test_root.py
+++ b/src/mailman/rest/tests/test_root.py
@@ -32,7 +32,7 @@ from mailman.config import config
 from mailman.core.system import system
 from mailman.testing.helpers import call_api
 from mailman.testing.layers import RESTLayer
-from six.moves.urllib_error import HTTPError
+from urllib.error import HTTPError
 
 
 
diff --git a/src/mailman/rest/tests/test_systemconf.py b/src/mailman/rest/tests/test_systemconf.py
index 0360baace..d7d0fe9a2 100644
--- a/src/mailman/rest/tests/test_systemconf.py
+++ b/src/mailman/rest/tests/test_systemconf.py
@@ -26,7 +26,7 @@ import unittest
 
 from mailman.testing.helpers import call_api
 from mailman.testing.layers import RESTLayer
-from six.moves.urllib_error import HTTPError
+from urllib.error import HTTPError
 
 
 
diff --git a/src/mailman/rest/tests/test_users.py b/src/mailman/rest/tests/test_users.py
index 2d85b3452..e009f63c1 100644
--- a/src/mailman/rest/tests/test_users.py
+++ b/src/mailman/rest/tests/test_users.py
@@ -33,7 +33,7 @@ from mailman.database.transaction import transaction
 from mailman.interfaces.usermanager import IUserManager
 from mailman.testing.helpers import call_api, configuration
 from mailman.testing.layers import RESTLayer
-from six.moves.urllib_error import HTTPError
+from urllib.error import HTTPError
 from zope.component import getUtility
 
 
diff --git a/src/mailman/runners/command.py b/src/mailman/runners/command.py
index b19d1aede..e7c732b09 100644
--- a/src/mailman/runners/command.py
+++ b/src/mailman/runners/command.py
@@ -28,12 +28,12 @@ __all__ = [
 # -owner.
 
 import re
-import six
 import logging
 
 from email.errors import HeaderParseError
 from email.header import decode_header, make_header
 from email.iterators import typed_subpart_iterator
+from io import StringIO
 from mailman.config import config
 from mailman.core.i18n import _
 from mailman.core.runner import Runner
@@ -80,7 +80,7 @@ class CommandFinder:
             # subject is a unicode object, convert it to ASCII ignoring all
             # bogus characters.  Otherwise, there's nothing in the subject
             # that we can use.
-            if isinstance(raw_subject, six.text_type):
+            if isinstance(raw_subject, str):
                 safe_subject = raw_subject.encode('us-ascii', 'ignore')
                 self.command_lines.append(safe_subject)
         # Find the first text/plain part of the message.
@@ -96,7 +96,7 @@ class CommandFinder:
             return
         body = part.get_payload()
         # text/plain parts better have string payloads.
-        assert isinstance(body, six.string_types), 'Non-string decoded payload'
+        assert isinstance(body, (bytes, str)), 'Non-string decoded payload'
         lines = body.splitlines()
         # Use no more lines than specified
         max_lines = int(config.mailman.email_commands_max_lines)
@@ -114,7 +114,7 @@ class CommandFinder:
             # Ensure that all the parts are unicodes.  Since we only accept
             # ASCII commands and arguments, ignore anything else.
             parts = [(part
-                      if isinstance(part, six.text_type)
+                      if isinstance(part, str)
                       else part.decode('ascii', 'ignore'))
                      for part in parts]
             yield parts
@@ -126,7 +126,7 @@ class Results:
     """The email command results."""
 
     def __init__(self, charset='us-ascii'):
-        self._output = six.StringIO()
+        self._output = StringIO()
         self.charset = charset
         print(_("""\
 The results of your email command are provided below.
@@ -139,7 +139,7 @@ The results of your email command are provided below.
 
     def __str__(self):
         value = self._output.getvalue()
-        assert isinstance(value, six.text_type), 'Not a unicode: %r' % value
+        assert isinstance(value, str), 'Not a string: %r' % value
         return value
 
 
diff --git a/src/mailman/runners/digest.py b/src/mailman/runners/digest.py
index c7882af02..ad6e0b1c5 100644
--- a/src/mailman/runners/digest.py
+++ b/src/mailman/runners/digest.py
@@ -30,6 +30,7 @@ from email.header import Header
 from email.mime.message import MIMEMessage
 from email.mime.text import MIMEText
 from email.utils import formatdate, getaddresses, make_msgid
+from io import StringIO
 from mailman.config import config
 from mailman.core.i18n import _
 from mailman.core.runner import Runner
@@ -39,8 +40,7 @@ from mailman.interfaces.member import DeliveryMode, DeliveryStatus
 from mailman.utilities.i18n import make
 from mailman.utilities.mailbox import Mailbox
 from mailman.utilities.string import oneline, wrap
-from six.moves import cStringIO as StringIO
-from six.moves.urllib_error import URLError
+from urllib.error import URLError
 
 
 log = logging.getLogger('mailman.error')
diff --git a/src/mailman/runners/nntp.py b/src/mailman/runners/nntp.py
index c19f06417..ac77b014c 100644
--- a/src/mailman/runners/nntp.py
+++ b/src/mailman/runners/nntp.py
@@ -28,10 +28,10 @@ import socket
 import logging
 import nntplib
 
+from io import StringIO
 from mailman.config import config
 from mailman.core.runner import Runner
 from mailman.interfaces.nntp import NewsgroupModeration
-from six.moves import cStringIO as StringIO
 
 
 COMMA = ','
diff --git a/src/mailman/testing/helpers.py b/src/mailman/testing/helpers.py
index f38641cf3..a869c8d55 100644
--- a/src/mailman/testing/helpers.py
+++ b/src/mailman/testing/helpers.py
@@ -67,8 +67,8 @@ from mailman.interfaces.styles import IStyleManager
 from mailman.interfaces.usermanager import IUserManager
 from mailman.runners.digest import DigestRunner
 from mailman.utilities.mailbox import Mailbox
-from six.moves.urllib_error import HTTPError
-from six.moves.urllib_parse import urlencode
+from urllib.error import HTTPError
+from urllib.parse import urlencode
 from zope import event
 from zope.component import getUtility
 
diff --git a/src/mailman/testing/mta.py b/src/mailman/testing/mta.py
index 98f1ffa8c..351ef631a 100644
--- a/src/mailman/testing/mta.py
+++ b/src/mailman/testing/mta.py
@@ -27,7 +27,7 @@ import logging
 from lazr.smtptest.controller import QueueController
 from lazr.smtptest.server import Channel, QueueServer
 from mailman.interfaces.mta import IMailTransportAgentLifecycle
-from six.moves.queue import Empty, Queue
+from queue import Empty, Queue
 from zope.interface import implementer
 
 
diff --git a/src/mailman/utilities/i18n.py b/src/mailman/utilities/i18n.py
index 8f6f27af4..1d3fbca6f 100644
--- a/src/mailman/utilities/i18n.py
+++ b/src/mailman/utilities/i18n.py
@@ -26,7 +26,6 @@ __all__ = [
 
 
 import os
-import six
 import sys
 import errno
 
@@ -200,8 +199,7 @@ def make(template_file, mlist=None, language=None, wrap=True,
         template = _(fp.read()[:-1])
     finally:
         fp.close()
-    assert isinstance(template, six.text_type), (
-        'Translated template is not unicode')
+    assert isinstance(template, str), 'Translated template is not a string'
     text = expand(template, kw)
     if wrap:
         return wrap_text(text)
diff --git a/src/mailman/utilities/importer.py b/src/mailman/utilities/importer.py
index 46140f282..8590d9b1b 100644
--- a/src/mailman/utilities/importer.py
+++ b/src/mailman/utilities/importer.py
@@ -45,7 +45,7 @@ from mailman.interfaces.nntp import NewsgroupModeration
 from mailman.interfaces.usermanager import IUserManager
 from mailman.utilities.filesystem import makedirs
 from mailman.utilities.i18n import search
-from six.moves.urllib_error import URLError
+from urllib.error import URLError
 from zope.component import getUtility
 
 
diff --git a/src/mailman/utilities/tests/test_import.py b/src/mailman/utilities/tests/test_import.py
index 68a02c720..b0ab9938d 100644
--- a/src/mailman/utilities/tests/test_import.py
+++ b/src/mailman/utilities/tests/test_import.py
@@ -29,7 +29,6 @@ __all__ = [
 
 
 import os
-import six
 import mock
 import unittest
 
@@ -53,8 +52,8 @@ from mailman.testing.layers import ConfigLayer
 from mailman.utilities.filesystem import makedirs
 from mailman.utilities.importer import import_config_pck, Import21Error
 from mailman.utilities.string import expand
+from pickle import load
 from pkg_resources import resource_filename
-from six.moves.cPickle import load
 from zope.component import getUtility
 
 
@@ -189,7 +188,7 @@ class TestBasicImport(unittest.TestCase):
         # moderator_password must not be unicode
         self._pckdict['mod_password'] = b'TESTVALUE'
         self._import()
-        self.assertNotIsInstance(self._mlist.moderator_password, six.text_type)
+        self.assertNotIsInstance(self._mlist.moderator_password, str)
         self.assertEqual(self._mlist.moderator_password, b'TESTVALUE')
 
     def test_newsgroup_moderation(self):