code: def add_scalar(self, k, v, n):
      self.data[k][n] = v
  
file_path: espnet/test/test_tensorboard.py
imports: from collections import defaultdict
  import chainer
  import numpy
  from espnet.utils.training.evaluator import BaseEvaluator
  from espnet.utils.training.tensorboard_logger import TensorboardLogger
label_desc: Use image node_id 2 for calling the DummyWriter obj's underlying member method code with example usage: obj.add_scalar(k, v, n) without return types