public function getDeclaredValue($only = false){
        if (isset($this->data['ShippingService']['DeclaredValue'])){
            if ($only){
                return $this->data['ShippingService']['DeclaredValue']['Amount'];
            } else {
                return $this->data['ShippingService']['DeclaredValue'];
            }
        } else {
            return false;
        }
    }