code: def triangulate(dataset):
          
          alg = vtk.vtkDataSetTriangleFilter()
          alg.SetInputData(dataset)
          alg.Update()
          return _get_output(alg)
docs: Returns an all triangle mesh.  More complex polygons will be broken
          down into triangles.
  
          Returns
          -------
          mesh : vtki.UnstructuredGrid
              Mesh containing only triangles.