# Managed spell leases

**🟡 Intermediate · Lesson 46**

Let a `with` block give the object back - ManagedSpellLease. conduit.managed_spell_meld(Spell) melds a managed spell and returns a lease: the `with` target is the leased object, and leaving the block releases it, even when the block raised (the block's exception is never swallowed). A lease releases exactly once: release() a second time does nothing, and lease.object raises once the object went back, because the pool may already have leased it again.

ReleaseManagedSpell().managed(obj) wraps an object you already hold - one meld returned, or one injected into your constructor - in the same kind of lease. managed_spell_meld refuses a spell that is not managed, before melding anything.

## Before you run

Use the [Intermediate guide](../../intermediate/index.md) 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

```bash
python UX_and_AIX_experiences/02_intermediate/46_managed_spell_leases.py
```

```powershell
py -3.14t UX_and_AIX_experiences/02_intermediate/46_managed_spell_leases.py
```

{download}`Download this collection <../../downloads/intermediate-examples.zip>` · [Source on GitHub](https://github.com/Synaptic724/melder/blob/90d52e0a12cb0743d62568d5a19ce954a54443bc/UX_and_AIX_experiences/02_intermediate/46_managed_spell_leases.py)

## Public surface

md.Conduit.managed_spell_meld, md.ManagedSpellLease (object,
                   release, released, with), md.ReleaseManagedSpell (managed,
                   describe), md.Existence.managed_spell_quantity, md.Existence.many,
                   md.Conduit.meld, md.Conduit.cleanup

## Code

```{literalinclude} ../../downloads/02_intermediate/46_managed_spell_leases.py
:language: python
:linenos:
```

## 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 intermediate examples](index.md) · [Level guide](../../intermediate/index.md)

## Related guides

- [Managed spell pools](../../intermediate/managed-spells.md)

## API contracts

- [Conduit](../../reference/api/resolution/conduit.md)
- [Existence](../../reference/api/resolution/existence.md)
- [ReleaseManagedSpell](../../reference/api/resolution/releasemanagedspell.md)
- [ManagedSpellLease](../../reference/api/resolution/managedspelllease.md)