code: def load_mtl(
      f: str,
      *,
      material_names: List[str],
      data_dir: str,
      device: Device = "cpu",
      path_manager: PathManager,
  ) -> Tuple[MaterialProperties, TextureImages]:
      """
      Load texture images and material reflectivity values for ambient, diffuse
      and specular light (Ka, Kd, Ks, Ns).
  
      Args:
          f: path to the material information.
          material_names: a list of the material names found in the .obj file.
          data_dir: the directory where the material texture files are located.
          device: Device (as str or torch.tensor) on which to return the new tensors.
          path_manager: PathManager for interpreting both f and material_names.
  
      Returns:
          material_properties: dict of properties for each material. If a material
                  does not have any properties it will have an empty dict.
                  {
                      material_name_1:  {
                          "ambient_color": tensor of shape (1, 3),
                          "diffuse_color": tensor of shape (1, 3),
                          "specular_color": tensor of shape (1, 3),
                          "shininess": tensor of shape (1)
                      },
                      material_name_2: {},
                      ...
                  }
          texture_images: dict of material names and texture images
                  {
                      material_name_1: (H, W, 3) image,
                      ...
                  }
      """
      material_properties, texture_files = _parse_mtl(
          f, path_manager, device
      )
      return _load_texture_images(
          material_names,
          data_dir,
          material_properties,
          texture_files,
          path_manager=path_manager,
      )
  
file_path: pytorch3d/pytorch3d/io/mtl_io.py
imports: import os
  import warnings
  from typing import Dict, List, Optional, Tuple
  import numpy
  import torch
  import torch.nn.functional
  from iopath.common.file_io import PathManager
  from pytorch3d.common.compat import meshgrid_ij
  from pytorch3d.common.datatypes import Device
  from pytorch3d.io.utils import _open_file, _read_image
label_desc: Use image node_id 7 for calling a global function with example usage: load_mtl(f) and returns: _load_texture_images