docstr: Inverse function to angle2class.
  As ScanNet only has axis-alined boxes so angles are always 0. 
docstr_tok: ["Inverse","function","to","angle2class",".","As","ScanNet","only","has","axis-alined","boxes","so","angles","are","always","0","."]
code: def class2angle(self, pred_cls, residual, to_label_format=True):
      """Inverse function to angle2class.
      As ScanNet only has axis-alined boxes so angles are always 0."""
      return 0
  
imports: import os
  import numpy
  import torch
  import logging
  from torch_geometric.data import InMemoryDataset
  from torch_points3d.datasets.segmentation.scannet import Scannet, NUM_CLASSES, IGNORE_LABEL
  from torch_points3d.metrics.object_detection_tracker import ObjectDetectionTracker
  from torch_points3d.datasets.base_dataset import BaseDataset, save_used_properties
  from torch_points3d.utils.box_utils import box_corners_from_param
label_desc: Use image node_id 3 for calling the ScannetDataset obj's underlying member method code with example usage: obj.class2angle(pred_cls, residual, to_label_format) and returns: int