Getting CheckboxGroup's active values in javascript code of RangeSlider/CustomJS

Hi,
I formed RangeSlider linked to CustomJS as:
callback = CustomJS(args=dict(source=… ), code=code )
range_slider = RangeSlider(… callback=callback )

I need to get CheckboxGroup’s active values in javascript code of RangeSlider/CustomJS

how can I do that?
regards

Just add the CheckboxGroup instance to the list of args of the callback and check its active property.