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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def scale(self, scalex, scaley=None, center=(0, 0)):
 """ 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. """

        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