docstr: Length of the batches to be loaded.
docstr_tok: ["Length","of","the","batches","to","be","loaded","."]
code: def __len__(self):
      """
      Length of the batches to be loaded.
      """
      raise NotImplementedError()
  
file_path: horovod/horovod/data/data_loader_base.py
imports: from queue import Queue, Empty
  from threading import Thread, Event
label_desc: Use image node_id 1 for calling the BaseDataLoader obj's underlying member method code with example usage: obj.__len__() without return types