code: def test_save_obj_invalid_shapes(self):
      # Invalid vertices shape
      verts = torch.FloatTensor([[0.1, 0.2, 0.3, 0.4]])  # (V, 4)
      faces = torch.LongTensor([[0, 1, 2]])
      with self.assertRaises(ValueError) as error:
          with NamedTemporaryFile(mode="w", suffix=".obj") as f:
              save_obj(Path(f.name), verts, faces)
      expected_message = "Argument 'verts' should either be empty or of shape (num_verts, 3)."
      self.assertTrue(expected_message, error.exception)
  
      # Invalid faces shape
      verts = torch.FloatTensor([[0.1, 0.2, 0.3]])
      faces = torch.LongTensor([[0, 1, 2, 3]])  # (F, 4)
      with self.assertRaises(ValueError) as error:
          with NamedTemporaryFile(mode="w", suffix=".obj") as f:
              save_obj(Path(f.name), verts, faces)
      expected_message = "Argument 'faces' should either be empty or of shape (num_faces, 3)."
      self.assertTrue(expected_message, error.exception)
  
imports: import os
  import unittest
  import warnings
  from collections import Counter
  from io import StringIO
  from pathlib import Path
  from tempfile import NamedTemporaryFile, TemporaryDirectory
  import torch
  from iopath.common.file_io import PathManager
  from pytorch3d.io import IO, load_obj, load_objs_as_meshes, save_obj
  from pytorch3d.io.mtl_io import _bilinear_interpolation_grid_sample, _bilinear_interpolation_vectorized, _parse_mtl
  from pytorch3d.renderer import TexturesAtlas, TexturesUV, TexturesVertex
  from pytorch3d.structures import join_meshes_as_batch, Meshes
  from pytorch3d.utils import torus
  from .common_testing import get_pytorch3d_dir, get_tests_dir, load_rgb_image, TestCaseMixin
label_desc: Use image node_id 14 for calling the TestMeshObjIO obj's underlying member method code with example usage: obj.test_save_obj_invalid_shapes() without return types