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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 to_polygon(self):
 """ Return a 4-cornered polygon equivalent to this rectangle """

        x,y = self.corners.T
        vertices = PixCoord(x=x, y=y)
        return PolygonPixelRegion(vertices=vertices, meta=self.meta,
                                  visual=self.visual)