class_docstr: emotion postprocess
class_docstr_tok: ["emotion","postprocess"]
docstr: update true label and pred label
docstr_tok: ["update","true","label","and","pred","label"]
code: def update_stats(self, prediction, stats):
      """update true label and pred label"""
      y_true = prediction["labels"]
      y_pred = np.argmax(prediction["softmax"], -1)
      stats[0] = np.append(stats[0], y_true)
      stats[1] = np.append(stats[1], y_pred)
      return stats
  
file_path: delta/delta/utils/postprocess/speech_cls_proc.py
imports: import os
  import pickle
  import collections
  import numpy
  from absl import logging
  from sklearn.metrics import confusion_matrix
  from delta import utils
  from delta.utils.postprocess.base_postproc import PostProc
  from delta.utils.register import registers
label_desc: Use image node_id 2 for calling the EmoPostProc obj's underlying member method code with example usage: obj.update_stats(prediction, stats) and returns: stats