code: def read_obj(in_file: str) -> Optional[Data]:
      vertices = []
      faces = []
  
      for k, v in yield_file(in_file):
          if k == "v":
              vertices.append(v)
          elif k == "f":
              faces.append(v)
  
      if not len(faces) or not len(vertices):
          return None
  
      pos = torch.tensor(vertices, dtype=torch.float)
      face = torch.tensor(faces, dtype=torch.long).t().contiguous()
  
      data = Data(pos=pos, face=face)
  
      return data
  
imports: from typing import Iterator, List, Optional, Tuple, Union
  import torch
  from torch_geometric.data import Data
label_desc: Use image node_id 2 for calling a global function with example usage: read_obj(in_file) and returns: data, None