code: def test_save_obj_invalid_indices(self):
      message_regex = "Faces have invalid indices"
      verts = torch.FloatTensor([[0.1, 0.2, 0.3]])
      faces = torch.LongTensor([[0, 1, 2]])
      with self.assertWarnsRegex(UserWarning, message_regex):
          with NamedTemporaryFile(mode="w", suffix=".obj") as f:
              save_obj(Path(f.name), verts, faces)
  
      faces = torch.LongTensor([[-1, 0, 1]])
      with self.assertWarnsRegex(UserWarning, message_regex):
          with NamedTemporaryFile(mode="w", suffix=".obj") as f:
              save_obj(Path(f.name), verts, faces)
  
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 15 for calling the TestMeshObjIO obj's underlying member method code with example usage: obj.test_save_obj_invalid_indices() without return types