Exercise 3: A Second, Distinct Exception Type — Possible Solution
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THE EXCEPTION CLASS AND EXTENDED MIDDLEWARE
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    class NotFoundError(Exception):
        pass

    def two_error_middleware(request, next_):
        try:
            return next_(request)
        except NotFoundError as e:
            return Response(f"404 Not Found: {e}", status=404)
        except ValueError as e:
            return Response(f"500 Internal Server Error: {e}", status=500)

    def crashes_with_value_error(request):
        raise ValueError("bad input")

    def crashes_with_not_found(request):
        raise NotFoundError("no such widget")

    app = App()
    app.use(two_error_middleware)
    app.add_route('GET', '/value-error', crashes_with_value_error)
    app.add_route('GET', '/not-found', crashes_with_not_found)

VERIFIED, REAL RESULTS (both against a real live server)
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    GET /value-error -> 500, b'500 Internal Server Error: bad input'
    GET /not-found    -> 404, b'404 Not Found: no such widget'

WHY THIS WORKS AS AN ANSWER
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The except clauses are ordered NotFoundError before ValueError - since
NotFoundError doesn't inherit from ValueError here, order between
these two specific clauses doesn't actually matter for correctness,
but it does reflect the real, general Python rule that a more specific
exception type should be listed before a more general one whenever a
real inheritance relationship exists between the two. Both routes are
verified against the same real running server rather than reasoning
about the try/except abstractly, confirming each exception type
produces its own distinct, correct status code and message rather
than one generic error path swallowing both.