message: Make sure the string returned is a string in Python 3 because of different string handling processes.
diff: @@ -130,10 +130,11 @@ class TPUClusterResolver(ClusterResolver):
  should_resolve = self._shouldResolve()
  if not project and should_resolve:
  - project = self._requestComputeMetadata('project/project-id')
  + project = compat.as_str(
  + self._requestComputeMetadata('project/project-id'))
  if not zone and should_resolve:
  - zone_path = self._requestComputeMetadata('instance/zone')
  + zone_path = compat.as_str(self._requestComputeMetadata('instance/zone'))
  zone = zone_path.split('/')[-1]
  self._project = project
  