Trouble in using gegl:contrast-curve filter from Python script

Hi,
I tried to using gegl:contrast-curve filter from Python with following code.


 set up for filters
        # add filter to top layer
        self.curve_filter0 = Gimp.DrawableFilter.new(self.rlayers[0], "gegl:contrast-curve", "Contrast Curve Filter")
        self.curve_filter0.set_blend_mode(Gimp.LayerMode.REPLACE)
        self.curve_filter0.set_opacity(1.0)
        self.config_c0 = self.curve_filter0.get_config()

        pointsX=[i/255. for i in range(256)]
        pointsY=[x * 0.5 for x in pointsX]
        curve=[p for xy in zip(pointsX,pointsY) for p in xy]

        self.config_c0.set_property("sampling-points", 256)
        self.config_c0.set_property("curve", curve)
        self.curve_filter0.update()
        self.rlayers[0].append_filter(self.curve_filter0)

Gegl reference says that gegl:contrast-curve takes “sampling-points” and “curve” as arg.

https://gegl.org/operations/gegl-contrast-curve.html

However I encountered following error messages.

“ self.config_c0.set_property(“curve”, curve)
TypeError: object of type GimpDrawableFilterConfig-gegl-contrast-curve' does not have property curve’”

And if I comment out this line and run this program, no error message found. It seems that gegl:contrast-curve only accepts “sampling-points” as property.

I also tried to use property name “Curve”, but the result was same.

Is this my fault or bug?