'Some course_keys are used without runs. This function calls the corresponding
fill_in_run function on the appropriate modulestore.'

def fill_in_run(self, course_key):

    store = self._get_modulestore_for_courselike(course_key)
    if (not hasattr(store, 'fill_in_run')):
        return course_key
    return store.fill_in_run(course_key)
