Not all. PyCharm has excellent static analysis capabilities for this. One just have to hint it with `assert isinstance(spam, Egg)` on occasions. Catches me to

Not all. PyCharm has excellent static analysis capabilities for this. One just have to hint it with `assert isinstance(spam, Egg)` on occasions. Catches me tons of bugs before interpreter ever hits them. Which is way nicer than getting an exception notification email with some live customer hitting 500 page because there's a TypeError in some obscure execution path you've never really tested.