code: def forward(self, x, pos, batch):
      idx = fps(pos, batch, ratio=self.ratio)
      row, col = radius(
          pos, pos[idx], self.r, batch, batch[idx], max_num_neighbors=64
      )
      edge_index = torch.stack([col, row], dim=0)
      x_dst = None if x is None else x[idx]
      x = self.conv((x, x_dst), (pos, pos[idx]), edge_index)
      pos, batch = pos[idx], batch[idx]
      return x, pos, batch
  
imports: import os.path
  import torch
  import torch.nn.functional
  import torch_geometric.transforms
  from torch_geometric.datasets import ModelNet
  from torch_geometric.loader import DataLoader
  from torch_geometric.nn import MLP, PointNetConv, fps, global_max_pool, radius
  from torch_geometric.typing import WITH_TORCH_CLUSTER
label_desc: Use image node_id 2 for calling the SAModule obj's underlying member method code with example usage: obj.forward(x, pos, batch) and returns: x,  pos,  batch