mypy: Added Dict, List and Set imports.

Fixed mypy errors associated with the upgrade.

zproject/backends.py

@@ -1,7 +1,7 @@
 from __future__ import absolute_import
 
 import logging
-from typing import Any, Set, Tuple, Optional, Text
+from typing import Any, Dict, List, Set, Tuple, Optional, Text
 
 from django.contrib.auth.backends import RemoteUserBackend
 from django.conf import settings

zproject/dev_settings.py

@@ -3,6 +3,7 @@
 # sample prod_settings.py file, with a few exceptions.
 from .prod_settings_template import *
 import os
+from typing import Set 
 
 LOCAL_UPLOADS_DIR = 'var/uploads'
 # Default to subdomains disabled in development until we can update

zproject/jinja2/backends.py

@@ -1,7 +1,7 @@
 from __future__ import absolute_import
 
 import sys
-from typing import Any, Optional, Union, Text
+from typing import Any, Dict, List, Optional, Union, Text
 
 import jinja2
 from django.utils import six

zproject/local_settings.py

@@ -9,6 +9,7 @@
 import platform
 import six.moves.configparser
 from base64 import b64decode
+from typing import Set
 
 config_file = six.moves.configparser.RawConfigParser() # type: ignore # https://github.com/python/typeshed/pull/206
 config_file.read("/etc/zulip/zulip.conf")