code: @SuppressWarnings("rawtypes")
  	public Set sunion(Object... keys) {
  		Jedis jedis = getJedis();
  		try {
  			Set<byte[]> data = jedis.sunion(keysToBytesArray(keys));
  			Set<Object> result = new HashSet<Object>();
  			valueSetFromBytesSet(data, result);
  			return result;
  		}
  		finally {close(jedis);}
  	}
docs: 返回多个集合的并集，多个集合由 keys 指定
  不存在的 key 被视为空集。