diff --git a/zerver/apps.py b/zerver/apps.py
index f41abb82b1..25c50e9640 100644
--- a/zerver/apps.py
+++ b/zerver/apps.py
@@ -1,12 +1,11 @@
 
-from django.apps import AppConfig
-from django.db.models.signals import post_migrate
-from django.core.cache import cache
-from django.conf import settings
-from typing import Any, Dict
-
 import logging
+from typing import Any, Dict
 
+from django.apps import AppConfig
+from django.conf import settings
+from django.core.cache import cache
+from django.db.models.signals import post_migrate
 
 def flush_cache(sender, **kwargs):
     # type: (AppConfig, **Any) -> None
diff --git a/zerver/filters.py b/zerver/filters.py
index 4ed40b2891..207c61d651 100644
--- a/zerver/filters.py
+++ b/zerver/filters.py
@@ -1,8 +1,8 @@
 
 from typing import Any, Dict
 
-from django.views.debug import SafeExceptionReporterFilter
 from django.http import HttpRequest
+from django.views.debug import SafeExceptionReporterFilter
 
 class ZulipExceptionReporterFilter(SafeExceptionReporterFilter):
     def get_post_parameters(self, request):
diff --git a/zerver/logging_handlers.py b/zerver/logging_handlers.py
index 140a507e31..e459846bf2 100644
--- a/zerver/logging_handlers.py
+++ b/zerver/logging_handlers.py
@@ -1,12 +1,11 @@
 # System documented in https://zulip.readthedocs.io/en/latest/logging.html
 
-from django.conf import settings
+import logging
+import platform
+import traceback
 from typing import Any, Dict, Optional
 
-import logging
-import traceback
-import platform
-
+from django.conf import settings
 from django.core import mail
 from django.http import HttpRequest
 from django.utils.log import AdminEmailHandler
diff --git a/zerver/middleware.py b/zerver/middleware.py
index 460baffcec..48586455de 100644
--- a/zerver/middleware.py
+++ b/zerver/middleware.py
@@ -1,32 +1,31 @@
 
-from typing import Any, AnyStr, Callable, Dict, Iterable, List, MutableMapping, Optional, Text
-
-from django.conf import settings
-from django.core.exceptions import DisallowedHost
-from django.utils.translation import ugettext as _
-from django.utils.deprecation import MiddlewareMixin
-
-from zerver.lib.response import json_error, json_response_from_error
-from zerver.lib.subdomains import get_subdomain
-from zerver.lib.exceptions import JsonableError, ErrorCode
-from django.db import connection
-from django.http import HttpRequest, HttpResponse, StreamingHttpResponse
-from zerver.lib.utils import statsd
-from zerver.lib.queue import queue_json_publish
-from zerver.lib.cache import get_remote_cache_time, get_remote_cache_requests
-from zerver.lib.bugdown import get_bugdown_time, get_bugdown_requests
-from zerver.models import Realm, flush_per_request_caches, get_realm
-from zerver.lib.exceptions import RateLimited
-from django.contrib.sessions.middleware import SessionMiddleware
-from django.views.csrf import csrf_failure as html_csrf_failure
-from django.utils.cache import patch_vary_headers
-from django.utils.http import cookie_date
-from django.shortcuts import redirect, render
-
+import cProfile
 import logging
 import time
-import cProfile
 import traceback
+from typing import Any, AnyStr, Callable, Dict, \
+    Iterable, List, MutableMapping, Optional, Text
+
+from django.conf import settings
+from django.contrib.sessions.middleware import SessionMiddleware
+from django.core.exceptions import DisallowedHost
+from django.db import connection
+from django.http import HttpRequest, HttpResponse, StreamingHttpResponse
+from django.shortcuts import redirect, render
+from django.utils.cache import patch_vary_headers
+from django.utils.deprecation import MiddlewareMixin
+from django.utils.http import cookie_date
+from django.utils.translation import ugettext as _
+from django.views.csrf import csrf_failure as html_csrf_failure
+
+from zerver.lib.bugdown import get_bugdown_requests, get_bugdown_time
+from zerver.lib.cache import get_remote_cache_requests, get_remote_cache_time
+from zerver.lib.exceptions import ErrorCode, JsonableError, RateLimited
+from zerver.lib.queue import queue_json_publish
+from zerver.lib.response import json_error, json_response_from_error
+from zerver.lib.subdomains import get_subdomain
+from zerver.lib.utils import statsd
+from zerver.models import Realm, flush_per_request_caches, get_realm
 
 logger = logging.getLogger('zulip.requests')
 
diff --git a/zerver/signals.py b/zerver/signals.py
index 41a1ad18fe..c4fa77af2a 100644
--- a/zerver/signals.py
+++ b/zerver/signals.py
@@ -1,12 +1,15 @@
 
-from django.dispatch import receiver
-from django.contrib.auth.signals import user_logged_in
-from django.conf import settings
-from django.template import loader
-from django.utils.timezone import get_current_timezone_name as timezone_get_current_timezone_name
-from django.utils.timezone import now as timezone_now
 from typing import Any, Dict, Optional
-from zerver.lib.send_email import send_email, FromAddress
+
+from django.conf import settings
+from django.contrib.auth.signals import user_logged_in
+from django.dispatch import receiver
+from django.template import loader
+from django.utils.timezone import \
+    get_current_timezone_name as timezone_get_current_timezone_name
+from django.utils.timezone import now as timezone_now
+
+from zerver.lib.send_email import FromAddress, send_email
 from zerver.models import UserProfile
 
 def get_device_browser(user_agent):
diff --git a/zerver/storage.py b/zerver/storage.py
index 51427fb3c6..e26439993d 100644
--- a/zerver/storage.py
+++ b/zerver/storage.py
@@ -2,7 +2,7 @@
 
 import os
 import shutil
-from typing import Dict, List, Any, Tuple
+from typing import Any, Dict, List, Tuple
 
 from django.conf import settings
 from django.contrib.staticfiles.storage import ManifestStaticFilesStorage