diff --git a/common/lib/xmodule/xmodule/combined_open_ended_module.py b/common/lib/xmodule/xmodule/combined_open_ended_module.py
index 76f2acd843..a3de34b427 100644
--- a/common/lib/xmodule/xmodule/combined_open_ended_module.py
+++ b/common/lib/xmodule/xmodule/combined_open_ended_module.py
@@ -10,7 +10,6 @@ import os
 import sys
 
 from pkg_resources import resource_string
-from timeinfo import TimeInfo
 
 from .capa_module import only_one, ComplexEncoder
 from .editing_module import EditingDescriptor
diff --git a/common/lib/xmodule/xmodule/peer_grading_module.py b/common/lib/xmodule/xmodule/peer_grading_module.py
index 0cb131ae9b..489459ceda 100644
--- a/common/lib/xmodule/xmodule/peer_grading_module.py
+++ b/common/lib/xmodule/xmodule/peer_grading_module.py
@@ -463,7 +463,8 @@ class PeerGradingModule(XModule):
 
 
         # grab all peer grading module descriptors for this course
-        peer_grading_modules = modulestore().get_items(['i4x', self.location.org, self.location.course, 'peergrading', None], self.system.course_id)
+        peer_grading_modules = modulestore().get_items(
+                ['i4x', self.location.org, self.location.course, 'peergrading', None], self.system.course_id)
 
         # construct a dictionary for fast lookups
         module_dict = {}
@@ -473,6 +474,9 @@ class PeerGradingModule(XModule):
                 module_dict[linked_location] = module
 
         def _find_corresponding_module_for_location(location):
+            '''
+            find the peer grading module that links to the given location
+            '''
             if location in module_dict:
                 return module_dict[location]
             else: