def METHOD_NAME(self, prefix, ns_uri, local_name):
    qname_string = QName(prefix, ns_uri, local_name).__str__()
    assertion = '{}:{}'.format(prefix, local_name) if prefix else local_name
    if qname_string is None:
        assert qname_string is assertion, 'str'
    else:
        assert qname_string == assertion, 'str'