code: def testStringRepr(self):
      self.assertEqual(
          str(
              proto_diff.ProtoPath(
                  ("observation", "actions", 1, "target")
              )
          ),
          "observation.actions[1].target",
      )
  
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 4 for calling the ProtoPathTest obj's underlying member method code with example usage: obj.testStringRepr() without return types