code: def start(self, key):
      self.running_time[key] = time.time()
      return self
  
imports: import collections
  import io
  import json
  import librosa
  import numpy
  import soundfile
  import time
  import torch
  from scipy.io.wavfile import read
  from .text import SOS_TOK, EOS_TOK
label_desc: Use image node_id 2 for calling the Timer obj's underlying member method code with example usage: obj.start(key) and returns: self