code: public function toNode(DOMDocument $document = null)
      {
          if (null === $document) {
              $document = new DOMDocument();
          }
  
          $node = $document->createElement('AddressKeyFormat');
  
          if ($this->getConsigneeName()) {
              $node->appendChild($document->createElement('ConsigneeName', $this->getConsigneeName()));
          }
  
          for ($i = 1; $i <= 3; $i++) {
              $line = $this->{'getAddressLine'.$i}();
              if ($line) {
                  $node->appendChild($document->createElement('AddressLine'.($i == 1 ? '' : $i), $line));
              }
          }
  
          for ($i = 1; $i <= 3; $i++) {
              $line = $this->{'getPoliticalDivision'.$i}();
              if ($line) {
                  $node->appendChild($document->createElement('PoliticalDivision'.$i, $line));
              }
          }
  
          if ($this->getPostcodePrimaryLow()) {
              $node->appendChild($document->createElement('PostcodePrimaryLow', $this->getPostcodePrimaryLow()));
          }
          if ($this->getPostcodeExtendedLow()) {
              $node->appendChild($document->createElement('PostcodeExtendedLow', $this->getPostcodeExtendedLow()));
          }
  
          if ($this->getCountryCode()) {
              $node->appendChild($document->createElement('CountryCode', $this->getCountryCode()));
          }
  
          if ($this->getSingleLineAddress()) {
              $node->appendChild($document->createElement('SingleLineAddress', $this->getSingleLineAddress()));
          }
  
          return $node;
      }
docs: @param null|DOMDocument $document
  
  @return DOMElement