public function removeNonSatNSschemaLocations()
    {
        $xsi = $this->dom->lookupPrefix('http://www.w3.org/2001/XMLSchema-instance');
        if (! $xsi) {
            return;
        }
        $schemaLocations = $this->xpathQuery("//@$xsi:schemaLocation");
        if ($schemaLocations->length === 0) {
            return;
        }
        for ($s = 0; $s < $schemaLocations->length; $s++) {
            $this->removeNonSatNSschemaLocation($schemaLocations->item($s));
        }
    }