code: def __init__(self, path, shuffle=True):
      self._db = diskcache.Index(path)
      self._shuffle = shuffle
      self._size = len(self._db)
  
imports: import numpy
  import os
  import six
  from ..utils import logger
  from ..utils.argtools import log_once
  from ..utils.serialize import loads
  from ..utils.develop import create_dummy_class
  from ..utils.loadcaffe import get_caffe_pb
  from ..utils.timer import timed_operation
  from ..utils.utils import get_tqdm
  from .base import DataFlowReentrantGuard, RNGDataFlow
  from .common import MapData
label_desc: Use image node_id 1 to create a new DiskCacheData object from inherited base classes: RNGDataFlow with example: obj = DiskCacheData(path, shuffle)