code: function fromXML($xmlElement)
      {
          if (isset($xmlElement->key)) { $this->key = (string)$xmlElement->key; }
          if (isset($xmlElement->value)) { $this->value = (string)$xmlElement->value; }
      }
docs: Initialization of the attachment from a simple xml element.
  
  @param SimpleXMLElement $xmlElement
  The xml element that is used to parse the attachment from.