def METHOD_NAME(self, course_key, fetch=False):
    """
    Return the user's bookmarks cache for a particular course.
    Arguments:
        course_key (CourseKey): course_key of the course whose bookmarks cache should be returned.
        fetch (Bool): if the bookmarks should be fetched and cached if they already aren't.
    """
    store = modulestore()
    course_key = store.fill_in_run(course_key)
    if course_key.run is None:
        return []
    cache_key = CACHE_KEY_TEMPLATE.format(self._user.id, course_key)
    bookmarks_cache = DEFAULT_REQUEST_CACHE.data.get(cache_key, None)
    if bookmarks_cache is None and fetch is True:
        bookmarks_cache = api.get_bookmarks(
            self._user, course_key=course_key, fields=DEFAULT_FIELDS
        )
        DEFAULT_REQUEST_CACHE.data[cache_key] = bookmarks_cache
    return bookmarks_cache