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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 list_metadata(self, resource):
 """ List all keys associated with the given resource. Args: resource (intern.resource.boss.BossResource) Returns: (list) Raises: requests.HTTPError on a failure. """

        self.metadata_service.set_auth(self._token_metadata)
        return self.metadata_service.list(resource)