docstr: sample a batch of indexes
  
  Args:
      batch_size (int): batch size
  
  Returns:
      batch of indexes
docstr_tok: ["sample","a","batch","of","indexes","Args",":","batch_size","(","int",")",":","batch","size","Returns",":","batch","of","indexes"]
code: def make_index(self, batch_size):
      """sample a batch of indexes
  
      Args:
          batch_size (int): batch size
  
      Returns:
          batch of indexes
      """
      batch_idx = np.random.randint(self._curr_size, size=batch_size)
      return batch_idx
  
file_path: PARL/parl/utils/replay_memory.py
imports: import numpy
  from parl.utils import logger
label_desc: Use image node_id 3 for calling the ReplayMemory obj's underlying member method code with example usage: obj.make_index(batch_size) and returns: batch_idx