code: def __len__(self):
      return self.length
  
file_path: PaddleOCR/ppocr/data/multi_scale_sampler.py
imports: from paddle.io import Sampler
  import paddle.distributed
  import numpy
  import random
  import math
label_desc: Use image node_id 5 for calling the MultiScaleSampler obj's underlying member method code with example usage: obj.__len__() and returns: self