code: public function toXML( XMLWriter $XMLWriter )
      {
          $XMLWriter->startElement( 'Telefone' );
  
          if (!is_null( $this->type )) {
              $XMLWriter->writeElement( 'Tipo', $this->type );
          } else {
              throw new RequiredFieldException( 'Field Type of the Phone object is required' );
          }
  
          if ($this->ddi) {
              $XMLWriter->writeElement( 'DDI', $this->ddi );
          }
  
          if ($this->ddd) {
              $XMLWriter->writeElement( 'DDD', $this->ddd );
          } else {
              throw new RequiredFieldException( 'Field DDD of the Phone object is required' );
          }
  
          if ($this->number) {
              $XMLWriter->writeElement( 'Numero', $this->number );
          } else {
              throw new RequiredFieldException( 'Field Number of the Phone object is required' );
          }
  
          if ($this->extension) {
              $XMLWriter->writeElement( 'Ramal', $this->extension );
          }
  
          $XMLWriter->endElement();
      }
docs: @param  \XMLWriter $XMLWriter
  
  @throws \RodrigoPedra\ClearSaleID\Exception\RequiredFieldException