Accidently removed Interpolation Function to fill NaN

So there was an interpolation function called interpolateInvalid, that was really helpfull with filling NaN gaps in data with an interpolation method of choice up to a certain gap size.

If i backtrack that right, it was accidently removed with 2.6, because it got renamed to interpolate at some point before, when interpolate was the name of a than deprecated function, that itself was merged into align.

Or do i miss something here? cant figure out how to fill gaps with linear interpolation for example, up to a certain size. Could be done with a somewhat elaborated reindex call maybe, but would counter the intuition of reindex since we dont have intent to change `index.

Or did we overcome to delegate that interpolation task to reindex and i forgot? I think its a little to arcane a call-prametrisation, for such a basic task.