code: def main(cmd=None):
      """LM training.
  
      Example:
  
          % python lm_train.py asr --print_config --optim adadelta
          % python lm_train.py --config conf/train_asr.yaml
      """
      LMTask.main(cmd=cmd)
  
label_desc: Use image node_id 2 for calling a global function with example usage: main(cmd) without return types