Thepixeldeveloper\Sitemap\OutputInterface::generateXML PHP Method

    public function generateXML(XMLWriter $XMLWriter);

 /**
  * @param OutputInterface $collection
  *
  * @return string
  */
 public function getOutput(OutputInterface $collection)
 {
     $xmlWriter = new XMLWriter();
     $xmlWriter->openMemory();
     $xmlWriter->startDocument('1.0', 'UTF-8');
     $xmlWriter->setIndent($this->isIndented());
     $xmlWriter->setIndentString($this->getIndentString());
     $collection->generateXML($xmlWriter);
     return trim($xmlWriter->flush(true));
 }