code: def testIndexing(self):
      path = proto_diff.ProtoPath(("observation", "actions", 1))
      self.assertEqual(path[0], "observation")
      self.assertEqual(path[1], "actions")
      self.assertEqual(path[-2], "actions")
      self.assertEqual(path[-1], 1)
  
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 8 for calling the ProtoPathTest obj's underlying member method code with example usage: obj.testIndexing() without return types