code: def ordering(self, type):
          
          result = []
          for child, ancestry in type.resolve():
              name = child.name
              if child.name is None:
                  continue
              if child.isattr():
                  name = '_%s' % child.name
              result.append(name)
          return result
docs: Get the attribute ordering defined in the specified
          XSD type information.
          @param type: An XSD type object.
          @type type: SchemaObject
          @return: An ordered list of attribute names.
          @rtype: list