code: def transformMesh(self, transformation):
          
          if isinstance(transformation, vtk.vtkMatrix4x4):
              tr = vtk.vtkTransform()
              tr.SetMatrix(transformation)
              transformation = tr
  
          tf = vtk.vtkTransformPolyDataFilter()
  
          tf.SetTransform(transformation)
          tf.SetInputData(self.polydata())
          tf.Update()
          self.PokeMatrix(vtk.vtkMatrix4x4())  # identity
          return self.updateMesh(tf.GetOutput())
docs: Apply this transformation to the polygonal `mesh`,
          not to the actor's transformation, which is reset.
  
          :param transformation: ``vtkTransform`` or ``vtkMatrix4x4`` object.