code: def test_v1(self):
      with pytest.raises(RuntimeError):
          dmtr = DemoMetric()
          dmtr.evaluate()
  
file_path: fastNLP/tests/core/metrics/test_metric.py
imports: import pytest
  from fastNLP import Metric
label_desc: Use image node_id 1 for calling the TestMetric obj's underlying member method code with example usage: obj.test_v1() without return types