code: def _alert_formatter(path, proto_a, proto_b):
      field_a = path.get_field(proto_a)
      if path[-2] == "alerts":
          field_b = path.get_field(proto_b)
          return "{} -> {}".format(
              sc_pb.Alert.Name(field_a), sc_pb.Alert.Name(field_b)
          )
  
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 a global function with example usage: _alert_formatter(path, proto_a, proto_b) and returns: str