Substituting for assessment

Without marking there is no signal, and without a signal people consistently overestimate what they have learned — because reading something and understanding something feel almost identical from the inside.

So build a check. Do the exercises rather than reading the answers. Build the small thing. Explain it in writing to somebody who will ask questions back. Anything where you can be visibly wrong works; anything where you cannot does not. That is the entire function assessment was serving.