code: def _parse_mtllibs(self):
          
          for mtllib in self.meta.mtllibs:
              try:
                  materials = self.material_parser_cls(
                      os.path.join(self.path, mtllib),
                      encoding=self.encoding,
                      strict=self.strict).materials
              except IOError:
                  raise IOError("Failed to load mtl file:".format(os.path.join(self.path, mtllib)))
  
              for name, material in materials.items():
                  self.wavefront.materials[name] = material
docs: Load mtl files