code: def __init__(self):
      super().__init__(backend="torch")
      self.register_element("count", 0)
      self.count = 2
  
file_path: fastNLP/tests/core/metrics/test_metric.py
imports: import pytest
  from fastNLP import Metric
label_desc: Use image node_id 1 to create a new DemoMetric1 object from inherited base classes: Metric with example: obj = DemoMetric1()