code: def __len__(self):
      return len(self.xml_list)
  
file_path: deep-learning-for-image-processing/others_project/kmeans_anchors/read_voc.py
imports: import os
  from tqdm import tqdm
  from lxml import etree
label_desc: Use image node_id 2 for calling the VOCDataSet obj's underlying member method code with example usage: obj.__len__() and returns: len