code: def getTransform(self):
          
          if "transform" in self.info.keys():
              T = self.info["transform"]
              return T
          else:
              T = self.GetMatrix()
              tr = vtk.vtkTransform()
              tr.SetMatrix(T)
              return tr
docs: Check if ``info['transform']`` exists and returns it.
          Otherwise return current user transformation
          (where the actor is currently placed).