code: def scale(self, scalex, scaley=None, center=(0, 0)):
          
          c0 = numpy.array(center)
          s = scalex if scaley is None else numpy.array((scalex, scaley))
          self.polygons = [(points - c0) * s + c0 for points in self.polygons]
          return self
docs: Scale this object.
  
          Parameters
          ----------
          scalex : number
              Scaling factor along the first axis.
          scaley : number or ``None``
              Scaling factor along the second axis.  If ``None``, same as
              ``scalex``.
          center : array-like[2]
              Center point for the scaling operation.
  
          Returns
          -------
          out : ``PolygonSet``
              This object.