code: def bounds(self):
          
          # return bounds including ONLY referenced vertices
          in_mesh = self.vertices[self.referenced_vertices]
          # get mesh bounds with min and max
          mesh_bounds = np.array([in_mesh.min(axis=0),
                                  in_mesh.max(axis=0)])
          # should not be mutable
          mesh_bounds.flags.writeable = False
          return mesh_bounds
docs: The axis aligned bounds of the faces of the mesh.
  
          Returns
          -----------
          bounds : (2, 3) float
            Bounding box with [min, max] coordinates