code: def plot_curvature(self, curv_type='mean', **kwargs):
          
          trisurf = self.extract_surface().tri_filter()
          return trisurf.plot_curvature(curv_type, **kwargs)
docs: Plots the curvature of the external surface of the grid
  
          Parameters
          ----------
          curv_type : str, optional
              One of the following strings indicating curvature types
  
              - mean
              - gaussian
              - maximum
              - minimum
  
          **kwargs : optional
              Optional keyword arguments.  See help(vtki.plot)
  
          Returns
          -------
          cpos : list
              Camera position, focal point, and view up.  Used for storing and
              setting camera view.