'Convert attribute values, that are references to other
objects, into I{qref}.  Qualfied using default document namespace.
Since many wsdls are written improperly: when the document does
not define a default namespace, the schema target namespace is used
to qualify references.'

def qualify(self):

    defns = self.root.defaultNamespace()
    if Namespace.none(defns):
        defns = self.schema.tns
    for a in self.autoqualified():
        ref = getattr(self, a)
        if (ref is None):
            continue
        if isqref(ref):
            continue
        qref = qualify(ref, self.root, defns)
        log.debug('%s,    convert    %s="%s"    to    %s', self.id, a, ref, qref)
        setattr(self, a, qref)
