code: def flip(self, angle, center=None):
          
          return self.rotate(-angle, center=center).flip_y(center=center).rotate(angle, center=center)
docs: Flip the shape in an arbitrary direction.
  
          Parameters
          ----------
          angle : array-like
              The angle, in radians counter-clockwise from the horizontal axis,
              defining the angle about which to flip the shape (of a line through `center`).
          center : array-like, optional
              The point about which to flip.
              If not passed, the center of the shape will be used.