diff --git a/common/djangoapps/util/sandboxing.py b/common/djangoapps/util/sandboxing.py
index 1e82b90a69..7d1c1da06f 100644
--- a/common/djangoapps/util/sandboxing.py
+++ b/common/djangoapps/util/sandboxing.py
@@ -3,6 +3,15 @@ from django.conf import settings
 
 
 def can_execute_unsafe_code(course_id):
+    """
+    Determine if this course is allowed to run unsafe code.
+
+    For use from the ModuleStore.  Checks the `course_id` against a list of whitelisted
+    regexes.
+
+    Returns a boolean, true if the course can run outside the sandbox.
+
+    """
     # To decide if we can run unsafe code, we check the course id against
     # a list of regexes configured on the server.
     for regex in settings.COURSES_WITH_UNSAFE_CODE: