code: def make_index(self, batch_size):
      batch_idx = np.random.randint(
          self._curr_size - 300 - 1, size=batch_size
      )
      return batch_idx
  
file_path: PARL/examples/NeurIPS2019-Learn-to-Move-Challenge/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