code: @Override
    public String psetex(final byte[] key, final long milliseconds, final byte[] value) {
      checkIsInMultiOrPipeline();
      client.psetex(key, milliseconds, value);
      return client.getStatusCodeReply();
    }
docs: PSETEX works exactly like {@link #setex(byte[], int, byte[])} with the sole difference that the
  expire time is specified in milliseconds instead of seconds. Time complexity: O(1)
  @param key
  @param milliseconds
  @param value
  @return Status code reply