Can author imply anything else? If reader knows better, why reader reads at all? Actually, before reading nobody can know what's in the writing, so author is naturally more knowledgeable.
Lesson is just a transfer of knowledge - which may turn out to be useless, but only after the fact.
...may turn out to be useless, but only after the fact.
I don't find it wrong, just irrelevant.
Oh, and using "data structure" to mean a "struct" is annoying for us old farts that learned the standard meaning, it's causing people to get confused. Actually, since classes are a data structures (in the old sense), the very title sounds like nonsense.
Nothing too bad, every day people does much worse in the Internet, but add the μαιευτικη´ and it comes out as inappropiate.
Lesson is just a transfer of knowledge - which may turn out to be useless, but only after the fact.