code: def class_to_segments(self):
      return {"class1": [0, 1, 2, 3, 4, 5], "class2": [6, 7, 8, 9]}
  
imports: import numpy
  import torch
  from torch_geometric.data import Data, Batch
  from torch_points3d.datasets.batch import SimpleBatch
  from torch_points3d.core.data_transform import MultiScaleTransform
  from torch_points3d.datasets.multiscale_data import MultiScaleBatch
  from torch_points3d.datasets.registration.pair import Pair, PairBatch, PairMultiScaleBatch, DensePairBatch
label_desc: Use image node_id 7 for calling the MockDataset obj's underlying member method code with example usage: obj.class_to_segments() and returns: dict