code: def __len__(self):
      return self._curr_size
  
file_path: PARL/benchmark/torch/iql/replay_buffer.py
imports: import numpy
  from parl.utils import logger
  import d4rl
  from tqdm import tqdm
label_desc: Use image node_id 4 for calling the ReplayMemory obj's underlying member method code with example usage: obj.__len__() and returns: self