code: def sample(self, batch_size):
      indexes = range(len(self._storage))
      idxes = [random.choice(indexes) for _ in range(batch_size)]
      return self._encode_sample(idxes)
  
imports: import argparse
  import os
  import random
  import time
  import gym
  import matplotlib.pyplot
  import numpy
  import tensorflow
  import tensorlayer
label_desc: Use image node_id 5 for calling the ReplayBuffer obj's underlying member method code with example usage: obj.sample(batch_size) and returns: self