🆕 🎓 Topic exceptions --- aside on exception's cause

[jameshughes89]

Related Issues or PRs

Related #148

What

Add an aside on exception causes to topic16.

Why

While acknowledging that this is outside the scope of the course, an aside on the topic seems fitting as it would be something to have students be familiar with. The idea being that when they come across them in the future, they're not intimidating.

Where

A new aside, something like topic16-cause.rst

Additional Notes

Perhaps low priority, but good idea nontheless.

[jameshughes89]

Closing because I do not know what this means, which means it's probably not too important.

[jameshughes89]

As brought up by @twentylemon offline, it's probably Exception#cause.

I will reopen for now, but it may still just get ignored once I have more time to think about it.