code: def stuff_classes(self):
      return torch.tensor([])
  
imports: import numpy
  import torch
  import random
  from torch_points3d.datasets.base_dataset import BaseDataset, save_used_properties
  from torch_points3d.datasets.segmentation.s3dis import S3DISSphere, S3DISCylinder, INV_OBJECT_LABEL
  import torch_points3d.core.data_transform
  from torch_points3d.metrics.panoptic_tracker import PanopticTracker
  from torch_points3d.datasets.panoptic.utils import set_extra_labels
label_desc: Use image node_id 3 for calling the PanopticS3DISBase obj's underlying member method code with example usage: obj.stuff_classes() and returns: torch