public function __construct($merchantKey, $wsdlUrl = self::WSDL_PRODUCTION_URL, $options = array()) { $this->merchantKey = $merchantKey; $defaultOptions = array('encoding' => 'UTF-8', 'trace' => true, 'exceptions' => true, 'cache_wsdl' => WSDL_CACHE_BOTH); $mergedOptions = array_merge($defaultOptions, $options); $this->soapClient = new SoapClient($wsdlUrl, $mergedOptions); $this->soapClient->setKeepNullProperties(false); $this->soapClient->setLowerCaseFirst(true); }