code: public function apply(array $options = [])
      {
          unset($this->config['trade_type']);
          unset($this->config['notify_url']);
          $this->gateway = $this->gateway_micropay;
          return $this->preOrder($options);
      }
docs: 应用并返回参数
  @param array $options
  @return array
  @throws \Pay\Exceptions\GatewayException