code: def __init__(self, id, cls, mapped_cls):
      self.id = id
      self.cls = cls
      self.mapped_cls = mapped_cls
  
imports: import numpy
  import nvidia.dali.fn
  import os
  import tempfile
  import json
  from nvidia.dali import Pipeline, pipeline_def
  from nose_utils import raises
  from nose2.tools import params
  from test_utils import compare_pipelines, get_dali_extra_path
label_desc: Use image node_id 1 to create a new sample_desc object  with example: obj = sample_desc(id, cls, mapped_cls)