class_docstr: Measures a scalar value (adapted from Detectron).
code: def get_win_avg(self):
      return np.mean(self.deque)
  
imports: from collections import deque
  import numpy
  import pycls.core.logging
  import torch
  from pycls.core.config import cfg
  from pycls.core.timer import Timer
label_desc: Use image node_id 5 for calling the ScalarMeter obj's underlying member method code with example usage: obj.get_win_avg() and returns: np