code: def _getter(self):
          
          def get_attr_value(obj):
              attr_str_value = obj.get(self._clark_name)
              if attr_str_value is None:
                  raise InvalidXmlError(
                      "required '%s' attribute not present on element %s" %
                      (self._attr_name, obj.tag)
                  )
              return self._simple_type.from_xml(attr_str_value)
          get_attr_value.__doc__ = self._docstring
          return get_attr_value
docs: Return a function object suitable for the "get" side of the attribute
          property descriptor.