code: def __len__(self):
      return self.num_samples
  
imports: import pickle
  import paddle
  import os
  import cv2
  import six
  import random
  import paddle
  import numpy
  import logging
  from PIL import Image
  from io import BytesIO
  from datasets.kv_helper import read_img_from_bin
label_desc: Use image node_id 3 for calling the CommonDataset obj's underlying member method code with example usage: obj.__len__() and returns: self