def parse_course_and_usage_keys(course_id, usage_id): """ Convert course and usage ID strings into key objects. Return a tuple of (course_key, usage_key), or throw an InvalidKeyError if the translation fails. """ course_key = CourseKey.from_string(course_id) usage_id = unquote_slashes(usage_id) usage_key = UsageKey.from_string(usage_id).map_into_course(course_key) return course_key, usage_key