Which preposition to use with unpractised

in Occurrences 11%

Westley Keyts's suggestion that Potts be weighted with pig-iron and dumped into the healing waters, drunk or sober, was the mere playfulness of an excellent butcher unpractised in sarcasm.

in Occurrences 5%

It was always locked; the lock was intricate; he had never so much as seen the key at close quarters and, even had opportunity offered, was quite unpractised in the art of taking impressions of locksa thing not done with accuracy quite so easily as seems sometimes to be assumed.

Which preposition to use with  unpractised