'Return a valid :class:`~opaque_keys.edx.keys.CourseKey` for this modulestore
that matches the supplied `org`, `course`, and `run`.
This key may represent a course that doesn\'t exist in this modulestore.'

def make_course_key(self, org, course, run):

    for (course_id, store) in self.mappings.iteritems():
        candidate_key = store.make_course_key(org, course, run)
        if (candidate_key == course_id):
            return candidate_key
    return self.default_modulestore.make_course_key(org, course, run)
