diff --git a/common/djangoapps/django_comment_common/models.py b/common/djangoapps/django_comment_common/models.py
index feba43a0eb..03372a9422 100644
--- a/common/djangoapps/django_comment_common/models.py
+++ b/common/djangoapps/django_comment_common/models.py
@@ -67,6 +67,10 @@ class Role(models.Model):
     # TODO the name of this method is a little bit confusing,
     # since it's one-off and doesn't handle inheritance later
     def inherit_permissions(self, role):
+        """
+        Make this role inherit permissions from the given role.
+        Permissions are only added, not removed. Does not handle inheritance.
+        """
         if role.course_id and role.course_id != self.course_id:
             logging.warning(
                 "%s cannot inherit permissions from %s due to course_id inconsistency",