How to use Php DOMDocument object in ci4

$result is post parameter .I want to try but not working.

error: Class 'App\Controllers\DOMDocument' not found

$resultDocument = new DOMDocument();

$resultDocument->loadXML($result);


$stateNode = $resultDocument->getElementsByTagName("state")->item(2);

$status = "";

if( $statusNode != null )

  $status = $stateNode->nodeVal;
Thank you for helps.

Sercan YANBULOGLU

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