code: def flip_x(self, center=None):
          
          if center is None:
              self.poly.flip()
          else:
              self.poly.flip(center[0])
docs: Flip the shape in the x direction, in-place.
  
          Parameters
          ----------
          center : array-like, optional
              Point about which to flip.
              If not passed, the center of the shape will be used.