code: def _calc_running_avg(self, engine):
      for k, v in engine.state.output.items():
          old_v = self.metrics.get(k, v)
          new_v = self.alpha * old_v + (1 - self.alpha) * v
          self.metrics[k] = new_v
  
imports: import sys
label_desc: Use image node_id 2 for calling the Progbar obj's underlying member method code with example usage: obj._calc_running_avg(engine) without return types