'Add a subreddit to a multi.'

@require_oauth2_scope('subscribe')
@validate(VUser(), VModhash(), multi=VMultiByPath('multipath', require_edit=True), sr_name=VSubredditName('srname', allow_language_srs=True), data=VValidatedJSON('model', multi_sr_data_json_spec))
@api_doc(api_section.multis, extends=GET_multi_subreddit)
def PUT_multi_subreddit(self, multi, sr_name, data):

    new = (not any(((sr.name.lower() == sr_name.lower()) for sr in multi.srs)))
    data['name'] = sr_name
    sr_props = self._add_multi_srs(multi, [data])
    sr = sr_props.items()[0][0]
    multi._commit()
    if new:
        response.status = 201
    return self._get_multi_subreddit(multi, sr)
