docstr: Return how many distillation labels/data have been recorded.
docstr_tok: ["Return","how","many","distillation","labels\/data","have","been","recorded","."]
code: def __len__(self) -> int:
      """
      Return how many distillation labels/data have been recorded.
      """
      raise NotImplementedError()
  
imports: from __future__ import annotations
  import logging
  import os
  from os import PathLike
  from pathlib import Path
  import shutil
  import tempfile
  from typing import Any, Dict, List, Literal
  import json_tricks
  from .utils import pickle_dump, pickle_load
label_desc: Use image node_id 1 for calling the _DistilStorage obj's underlying member method code with example usage: obj.__len__() without return types