code: def _get_num_classes(cls):
      return len(cls.CATEGORY_META_INFO)
  
imports: import json
  import copy
  import os
  import numpy
  import paddle
  from paddleseg.transforms import Compose
  from paddlepanseg.cvlibs import build_info_dict
label_desc: Use image node_id 7 for calling the COCOStylePanopticDataset obj's underlying member method code with example usage: obj._get_num_classes(cls) and returns: len