code: def update_columns_dict(self, kwargs):
          
          super(Mesh, self).update_columns_dict(kwargs)
  
          # if kwargs.get('vnormals', None) is not None or kwargs.get('tnormals', None) is not None:
              # self._compute_mus()
          if kwargs.get('triangles', None) is not None:
              # reset visibilities and velocities so that they are reset
              # when next queried
              self.update_columns(visibilities=None, velocities=None)
docs: TODO: add documentation