code: def num_proposal(self):
      return self.center.shape[1]
  
file_path: torch-points3d/torch_points3d/modules/VoteNet/votenet_results.py
imports: import torch
  from torch_geometric.data import Data
  import numpy
  from typing import List
  from torch_points3d.core.losses.huber_loss import nn_distance
  from torch_points3d.utils.box_utils import box_corners_from_param, nms_samecls
  from torch_points3d.datasets.object_detection.box_data import BoxData
label_desc: Use image node_id 4 for calling the VoteNetResults obj's underlying member method code with example usage: obj.num_proposal() and returns: self