code: def reversed(self):
          
          new_cub = CubicBezier(self.end, self.control2, self.control1,
                                self.start)
          if self._length_info['length']:
              new_cub._length_info = self._length_info
              new_cub._length_info['bpoints'] = (
                  self.end, self.control2, self.control1, self.start)
          return new_cub
docs: returns a copy of the CubicBezier object with its orientation
          reversed.