code: def test_v2(self):
      dmtr = DemoMetric1()
      assert 3 == dmtr.evaluate()
  
file_path: fastNLP/tests/core/metrics/test_metric.py
imports: import pytest
  from fastNLP import Metric
label_desc: Use image node_id 2 for calling the TestMetric obj's underlying member method code with example usage: obj.test_v2() without return types