Catching the right error — not 'anything that goes wrong' (step 9/9) · error handling

Checkpoint

One last thing before we move on. Same surface as a write step — but the lesson doesn't complete until this passes.

Last drill. Cursor wrote summarize_order to look up an item's price, multiply it by a quantity it parses from a string, and return a total. Three lines, three failure modes:

prices[item] raises KeyError if the item isn't in the catalog.
int(qty_text) raises ValueError if the string isn't a number.
everything else (a real bug you didn't anticipate) should crash.

The starter has a single except Exception: that swallows all three. Fix it: catch KeyError and ValueError together with a tuple, return the string "invalid" for either case, and let any other exception fly through.

Expected output:

20
invalid
invalid

Checkpoint

One last thing before we move on. Same surface as a write step — but the lesson doesn't complete until this passes.

Last drill. Cursor wrote summarize_order to look up an item's price, multiply it by a quantity it parses from a string, and return a total. Three lines, three failure modes:

prices[item] raises KeyError if the item isn't in the catalog.
int(qty_text) raises ValueError if the string isn't a number.
everything else (a real bug you didn't anticipate) should crash.

Expected output:

20
invalid
invalid

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Catching the right error — not 'anything that goes wrong' — step 9 of 9