code: def reset_lstm_state(self):
      s = self.state
      z = tf.zeros_like(s[0].c)
      ops = []
      for k in range(NUM_LAYER):
          ops.append(s[k].c.assign(z))
          ops.append(s[k].h.assign(z))
      return tf.group(*ops, name="reset_lstm_state")
  
file_path: tensorpack/examples/PennTreebank/PTB-LSTM.py
imports: import argparse
  import numpy
  import os
  import tensorflow
  from tensorpack import *
  from tensorpack.tfutils import gradproc, optimizer, summary
  from tensorpack.utils import logger
  from tensorpack.utils.argtools import memoized_ignoreargs
  from tensorpack.utils.fs import download, get_dataset_path
  import reader
  from reader import ptb_producer
label_desc: Use image node_id 3 for calling the Model obj's underlying member method code with example usage: obj.reset_lstm_state() and returns: tf