code: def mesh(self, vertices=None, faces=None, vertex_colors=None,
               face_colors=None, color=(0.5, 0.5, 1.), fname=None,
               meshdata=None):
          
          self._configure_3d()
          if fname is not None:
              if not all(x is None for x in (vertices, faces, meshdata)):
                  raise ValueError('vertices, faces, and meshdata must be None '
                                   'if fname is not None')
              vertices, faces = read_mesh(fname)[:2]
          if meshdata is not None:
              if not all(x is None for x in (vertices, faces, fname)):
                  raise ValueError('vertices, faces, and fname must be None if '
                                   'fname is not None')
          else:
              meshdata = MeshData(vertices, faces)
          mesh = scene.Mesh(meshdata=meshdata, vertex_colors=vertex_colors,
                            face_colors=face_colors, color=color,
                            shading='smooth')
          self.view.add(mesh)
          self.view.camera.set_range()
          return mesh
docs: Show a 3D mesh
  
          Parameters
          ----------
          vertices : array
              Vertices.
          faces : array | None
              Face definitions.
          vertex_colors : array | None
              Vertex colors.
          face_colors : array | None
              Face colors.
          color : instance of Color
              Color to use.
          fname : str | None
              Filename to load. If not None, then vertices, faces, and meshdata
              must be None.
          meshdata : MeshData | None
              Meshdata to use. If not None, then vertices, faces, and fname
              must be None.
  
          Returns
          -------
          mesh : instance of Mesh
              The mesh.