diff --git a/lms/djangoapps/courseware/courses.py b/lms/djangoapps/courseware/courses.py
index 625453aad0..8634ba895d 100644
--- a/lms/djangoapps/courseware/courses.py
+++ b/lms/djangoapps/courseware/courses.py
@@ -51,6 +51,7 @@ def get_course_by_id(course_id, depth=0):
     except InvalidLocationError:
         raise Http404("Invalid location")
 
+
 def get_course_with_access(user, course_id, action, depth=0):
     """
     Given a course_id, look up the corresponding course descriptor,
@@ -85,24 +86,24 @@ def course_image_url(course):
     if course.static_asset_path or modulestore().get_modulestore_type(course.location.course_id) == XML_MODULESTORE_TYPE:
         return '/static/' + (course.static_asset_path or getattr(course, 'data_dir', '')) + "/images/course_image.jpg"
     else:
-        loc = course.location._replace(tag='c4x', category='asset', name=course.course_image)
+        loc = course.location.replace(tag='c4x', category='asset', name=course.course_image)
         _path = StaticContent.get_url_path_from_location(loc)
         return _path
 
 
-def find_file(fs, dirs, filename):
+def find_file(filesystem, dirs, filename):
     """
     Looks for a filename in a list of dirs on a filesystem, in the specified order.
 
-    fs: an OSFS filesystem
+    filesystem: an OSFS filesystem
     dirs: a list of path objects
     filename: a string
 
     Returns d / filename if found in dir d, else raises ResourceNotFoundError.
     """
-    for d in dirs:
-        filepath = path(d) / filename
-        if fs.exists(filepath):
+    for directory in dirs:
+        filepath = path(directory) / filename
+        if filesystem.exists(filepath):
             return filepath
     raise ResourceNotFoundError("Could not find {0}".format(filename))
 
@@ -146,7 +147,7 @@ def get_course_about_section(course, section_key):
 
             request = get_request_for_thread()
 
-            loc = course.location._replace(category='about', name=section_key)
+            loc = course.location.replace(category='about', name=section_key)
 
             # Use an empty cache
             field_data_cache = FieldDataCache([], course.id, request.user)
@@ -182,7 +183,6 @@ def get_course_about_section(course, section_key):
     raise KeyError("Invalid about key " + str(section_key))
 
 
-
 def get_course_info_section(request, course, section_key):
     """
     This returns the snippet of html to be rendered on the course info page,
@@ -194,8 +194,6 @@ def get_course_info_section(request, course, section_key):
     - updates
     - guest_updates
     """
-
-
     loc = Location(course.location.tag, course.location.org, course.location.course, 'course_info', section_key)
 
     # Use an empty cache
@@ -237,13 +235,13 @@ def get_course_syllabus_section(course, section_key):
 
     if section_key in ['syllabus', 'guest_syllabus']:
         try:
-            fs = course.system.resources_fs
+            filesys = course.system.resources_fs
             # first look for a run-specific version
             dirs = [path("syllabus") / course.url_name, path("syllabus")]
-            filepath = find_file(fs, dirs, section_key + ".html")
-            with fs.open(filepath) as htmlFile:
+            filepath = find_file(filesys, dirs, section_key + ".html")
+            with filesys.open(filepath) as html_file:
                 return replace_static_urls(
-                    htmlFile.read().decode('utf-8'),
+                    html_file.read().decode('utf-8'),
                     getattr(course, 'data_dir', None),
                     course_id=course.location.course_id,
                     static_asset_path=course.static_asset_path,
diff --git a/lms/djangoapps/courseware/tests/test_courses.py b/lms/djangoapps/courseware/tests/test_courses.py
index ee05a483a5..71c314a48b 100644
--- a/lms/djangoapps/courseware/tests/test_courses.py
+++ b/lms/djangoapps/courseware/tests/test_courses.py
@@ -1,4 +1,7 @@
 # -*- coding: utf-8 -*-
+"""
+Tests for course access
+"""
 import mock
 
 from django.test import TestCase
@@ -9,11 +12,12 @@ from xmodule.modulestore.django import get_default_store_name_for_current_reques
 
 CMS_BASE_TEST = 'testcms'
 
+
 class CoursesTest(TestCase):
     def test_get_course_by_id_invalid_chars(self):
         """
         Test that `get_course_by_id` throws a 404, rather than
-        an exception, when faced with unexpected characters 
+        an exception, when faced with unexpected characters
         (such as unicode characters, and symbols such as = and ' ')
         """
         with self.assertRaises(Http404):
@@ -30,13 +34,12 @@ class CoursesTest(TestCase):
         self.assertEqual("//{}/".format(CMS_BASE_TEST), get_cms_course_link_by_id("too/too/many/slashes"))
         self.assertEqual("//{}/org/num/course/name".format(CMS_BASE_TEST), get_cms_course_link_by_id('org/num/name'))
 
-
     @mock.patch('xmodule.modulestore.django.get_current_request_hostname', mock.Mock(return_value='preview.localhost'))
-    @override_settings(HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS={'preview\.': 'draft'})
-    def test_default_modulestore_preview_mapping(self):   
+    @override_settings(HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS={r'preview\.': 'draft'})
+    def test_default_modulestore_preview_mapping(self):
         self.assertEqual(get_default_store_name_for_current_request(), 'draft')
 
     @mock.patch('xmodule.modulestore.django.get_current_request_hostname', mock.Mock(return_value='localhost'))
-    @override_settings(HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS={'preview\.': 'draft'})
+    @override_settings(HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS={r'preview\.': 'draft'})
     def test_default_modulestore_published_mapping(self):
         self.assertEqual(get_default_store_name_for_current_request(), 'default')