Errors & try/except

Python raises exceptions when something goes wrong. You can catch them.

The pattern

try:
    risky()
except SomeError as e:
    handle(e)
finally:
    cleanup()

Best practices

• Catch the narrowest exception you can. Bare except: hides real bugs.
• Don't catch what you can't handle. Letting an error bubble up is often the right call.
• Use finally: for cleanup that must run either way.

Try it

1. Add a check for negative b and raise a ValueError.
2. Wrap the calls in a try and print every error you get.