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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def resources(self):
 """ Return all the resources which this function refer to. :return: resources :rtype: list .. seealso:: :class:`odps.models.Resource` """


        if self._resources_objects is not None:
            return self._resources_objects

        resources = self.parent.parent.resources
        resources = [resources[name] for name in self._resources]
        self._resources_objects = resources
        return resources