code: def testNoDiffs(self):
      a = sc_pb.ResponseObservation()
      b = sc_pb.ResponseObservation()
      diff = proto_diff.compute_diff(a, b)
      self.assertIsNone(diff)
  
imports: from absl.testing import absltest
  from pysc2.lib import proto_diff
  from s2clientprotocol import sc2api_pb2
  from s2clientprotocol import score_pb2
label_desc: Use image node_id 1 for calling the ProtoDiffTest obj's underlying member method code with example usage: obj.testNoDiffs() without return types