public function setPaymentOptions($payKey, $receivers)
    {
        $this->post = $this->setRequestData([
            'requestEnvelope' => $this->setEnvelope(),
            'payKey'          => $payKey,
        ])->merge([
            'receiverOptions' => $this->setPaymentOptionsReceiverDetails($receivers),
        ]);

        return $this->doPayPalRequest('SetPaymentOptions');
    }