code: def capacity(self):
      return self._capacity
  
imports: import os.path
  from collections import OrderedDict
  import cv2
  from cv2 import CAP_PROP_FOURCC, CAP_PROP_FPS, CAP_PROP_FRAME_COUNT, CAP_PROP_FRAME_HEIGHT, CAP_PROP_FRAME_WIDTH, CAP_PROP_POS_FRAMES, VideoWriter_fourcc
  from annotator.uniformer.mmcv.utils import check_file_exist, mkdir_or_exist, scandir, track_progress
label_desc: Use image node_id 2 for calling the Cache obj's underlying member method code with example usage: obj.capacity() and returns: self