code: def get_metric(self) -> dict:
      return {
          "t1": self.t1.get_scalar(),
          "t2": self.t2.get_scalar(),
          "t3": self.t3.get_scalar(),
      }
  
file_path: fastNLP/tests/core/metrics/test_element_cal_element.py
imports: import pytest
  from fastNLP.core.metrics import Metric
  from fastNLP.envs.imports import _NEED_IMPORT_TORCH
  from .utils import find_free_network_port, setup_ddp
label_desc: Use image node_id 3 for calling the MyMetric obj's underlying member method code with example usage: obj.get_metric() and returns: dict