/**
  * {@inheritDoc}
  *
  * @return string
  */
 public function toXML()
 {
     return XmlUtils::toXml($this, new MessageType(MessageType::PAYMENT));
 }
 /**
  * {@inheritDoc}
  */
 public function toXml()
 {
     return XmlUtils::toXml($this, new MessageType(MessageType::THREE_D_SECURE));
 }