//System.out.println("[a:elem_a].lookupPrefix('http://www.example.com', false) == ns1");
Assertion.verify(elem.lookupPrefix("http://www.example.com").equals("ns1"),
"[a:elem_a].lookupPrefix(http://www.example.com)==ns1");
Assertion.verify(elem.lookupNamespaceURI("xsi").equals("http://www.w3.org/2001/XMLSchema-instance"),
"[a:elem_a].lookupNamespaceURI('xsi') == 'http://www.w3.org/2001/XMLSchema-instance'" );
} else {
Assertion.verify( elem.lookupPrefix("http://www.example.com") == null,"lookupPrefix(http://www.example.com)==null");
}