Explicit cleanup

🟢 Beginner · Lesson 10

Teardown is a verb you own - conduit.cleanup() then book.cleanup(), in that order, and a cleaned book refuses further work loudly. (Disposal hooks you registered fire during this walk - see 08/35.)

Before you run

Use the Beginner guide for prerequisite concepts. Run from a checkout with Melder installed and Python 3.14 free-threading selected. The collection download includes the level's local helper modules.

Run the saved script

python UX_and_AIX_experiences/01_beginner/10_explicit_cleanup.py

py -3.14t UX_and_AIX_experiences/01_beginner/10_explicit_cleanup.py

Download this collection · Source on GitHub

Public surface

cleanup verbs, post-cleanup guards

Code

"""
TIER: beginner (10)
GOAL: Teardown is a verb you own - conduit.cleanup() then book.cleanup(),
      in that order, and a cleaned book refuses further work loudly.
      (Disposal hooks you registered fire during this walk - see 08/35.)
SURFACE EXERCISED: cleanup verbs, post-cleanup guards
"""
import melder as md


class Service:
    pass


def main() -> None:
    book = md.Spellbook()
    book.bind(spell=Service, existence="unique")
    conduit = book.conjure()
    assert isinstance(conduit.meld("Service"), Service)

    conduit.cleanup()
    book.cleanup()
    print("world torn down: conduit first, book second")

    try:
        book.bind(spell=Service, existence="unique")
        print("post-cleanup bind unexpectedly succeeded")
    except Exception as err:
        print("cleaned book guards itself:", type(err).__name__)


if __name__ == "__main__":
    main()

Check the outcome

The script contains its own assertions or demonstrated refusal paths. Run it to evaluate those checks against your installed version. The code above is taken directly from the saved file; no run output is invented here.

More beginner examples · Level guide