I'm pretty sure that doesn't qualify. To my mind that's training or study of a trade which is distinct from practicing (ie getting paid for) it.
Where it gets weird is cases where the delineation between practice and study is unclear. Researchers are professionally employed to study things. On the clock professional development is study, but it's paid for by your employer. Freelancers manage their own time making even the distinction between paid and unpaid work unclear in some cases - were you studying as part of a current contract, or to better prepare yourself to take on similar work in the future?
Where it gets weird is cases where the delineation between practice and study is unclear. Researchers are professionally employed to study things. On the clock professional development is study, but it's paid for by your employer. Freelancers manage their own time making even the distinction between paid and unpaid work unclear in some cases - were you studying as part of a current contract, or to better prepare yourself to take on similar work in the future?