def scale_xy(self, x=0, y=None):
        """Scale element separately across the two axes x and y.
            If y is not provided, it is assumed equal to x (according to the
            W3 specification).

        Parameters
        ----------
        x : float
            x-axis scaling factor. To scale down x < 1, scale up x > 1.
        y : (optional) float
            y-axis scaling factor. To scale down y < 1, scale up y > 1.

        """
        self.root.set("transform", "%s scale(%f %f)" %
                      (self.root.get("transform") or '',
                       x, y if y is not None else ''))
Scale element separately across the two axes x and y.
            If y is not provided, it is assumed equal to x (according to the
            W3 specification).

        Parameters
        ----------
        x : float
            x-axis scaling factor. To scale down x < 1, scale up x > 1.
        y : (optional) float
            y-axis scaling factor. To scale down y < 1, scale up y > 1.