private function setApiProvider($credentials)
    {
        if ($this instanceof \Srmklive\PayPal\Services\AdaptivePayments) {
            $this->setAdaptivePaymentsOptions();
        } elseif ($this instanceof \Srmklive\PayPal\Services\ExpressCheckout) {
            $this->setExpressCheckoutOptions($credentials);
        } else {
            throw new \Exception('Invalid api credentials provided for PayPal!. Please provide the right api credentials.');
        }
    }