INCR-206 ran modernize and isort on files (#20464)

ran modernize and isort on openedx/core/djangoapps/header_control and
openedx/core/djangoapps/session_inactivity_timeout

openedx/core/djangoapps/header_control/decorators.py

@@ -2,6 +2,8 @@
 Middleware decorator for removing headers.
 """
 
+from __future__ import absolute_import
+
 from functools import wraps
 
 from openedx.core.djangoapps.header_control import force_header_for_response, remove_headers_from_response

openedx/core/djangoapps/header_control/middleware.py

@@ -1,6 +1,7 @@
 """
 Middleware used for adjusting headers in a response before it is sent to the end user.
 """
+import six
 
 
 class HeaderControlMiddleware(object):
@@ -18,7 +19,7 @@ class HeaderControlMiddleware(object):
         for header in getattr(response, 'remove_headers', []):
             del response[header]
 
-        for header, value in getattr(response, 'force_headers', {}).iteritems():
+        for header, value in six.iteritems(getattr(response, 'force_headers', {})):
             response[header] = value
 
         return response

openedx/core/djangoapps/header_control/tests/test_decorators.py

@@ -1,6 +1,9 @@
 """Tests for remove_headers and force_header decorator. """
+from __future__ import absolute_import
+
 from django.http import HttpRequest, HttpResponse
 from django.test import TestCase
+
 from openedx.core.djangoapps.header_control.decorators import force_header, remove_headers
 
 

openedx/core/djangoapps/header_control/tests/test_middleware.py

@@ -1,6 +1,9 @@
 """Tests for header_control middleware."""
+from __future__ import absolute_import
+
 from django.http import HttpRequest, HttpResponse
 from django.test import TestCase
+
 from openedx.core.djangoapps.header_control import force_header_for_response, remove_headers_from_response
 from openedx.core.djangoapps.header_control.middleware import HeaderControlMiddleware
 

openedx/core/djangoapps/session_inactivity_timeout/middleware.py

@@ -8,6 +8,8 @@ To enable this feature, set in a settings.py:
 
 This was taken from StackOverflow (http://stackoverflow.com/questions/14830669/how-to-expire-django-session-in-5minutes)
 """
+from __future__ import absolute_import
+
 from datetime import datetime, timedelta
 
 from django.conf import settings