code: def __len__(self):
      return len(self.x)
  
imports: import os
  import cv2
  import numpy
  from PIL import Image
  import paddle
  from paddle.io import Dataset
  from paddle.vision import transforms
  from qinspector.cvlib.workspace import register
label_desc: Use image node_id 3 for calling the MVTecDataset obj's underlying member method code with example usage: obj.__len__() and returns: len