Add doctrings to module/class.

common/djangoapps/edxmako/apps.py

-
+"""
+Configuration for the edxmako Django application.
+"""
 from django.apps import AppConfig
 from django.conf import settings
 from . import add_lookup, clear_lookups
 
 
 class EdxMakoConfig(AppConfig):
+    """
+    Configuration class for the edxmako Django application.
+    """
     name = 'edxmako'
     verbose_name = "edX Mako Templating"