I'm trying to evaluate if a keyframe is set at specific frame, so I can switch between live input value and keyframed values. Eventually I would like to use this to prevent unwanted animation overwrite on already set keyframes (I'm using external button and I want keyframes set only if the button is pressed, passing live values for unkeyframed frames).

Is there any python function to get this? I've tried hou.KeyframeValueNotSet but it just reports “This keyframe value is not set.” on every frame, even when a keyframe is actually set.

I would be glad for any advice.

Thanks!