AI wrote a Coord dataclass meant to be a value object — never
mutated after construction. The decorator is plain @dataclass,
which leaves it mutable, so the line origin.x = 999 silently
succeeds when it shouldn't.
Add frozen=True to the decorator on line 3 so the assignment
raises FrozenInstanceError. The except block catches it and prints
the class name.
Expected output:
blocked: FrozenInstanceError
The break is on line 3 — but read the whole snippet first.