my $xpc = XML::LibXML::XPathContext->new($dom);
$xpc->registerNs('gml', 'http://graphml.graphdrawing.org/xmlns');

if (my $graphNode = @{$xpc->findnodes('/gml:graphml/gml:graph')}[0] ) {
	if ($graphNode->hasAttributes()) {
		my $directed = $graphNode->getAttribute('edgedefault') || '';
		print "edgedefault = '$directed'\n";
	}
}
else {
	print "did not find graph node edgedefault value\n";
}