Braintree\CreditCardGateway::_doUpdate PHP Method

    private function _doUpdate($httpVerb, $subPath, $params)
    {
        $fullPath = $this->_config->merchantPath() . $subPath;
        $response = $this->_http->{$httpVerb}($fullPath, $params);
        return $this->_verifyGatewayResponse($response);
    }