``` unison
structural ability Ask where ask : Nat

ability Zoot where
  zoot : Nat

Ask.provide : '{Zoot} Nat -> '{Ask} r -> r
Ask.provide answer asker =
  h = cases
    {r}                 -> r
    {Ask.ask -> resume} -> handle resume !answer with h
  handle !asker with h

dialog = Ask.provide 'zoot '("Awesome number: " ++ Nat.toText Ask.ask ++ "!")

> dialog
```

``` ucm

  Loading changes detected in scratch.u.

  The expression in red needs the {Zoot} ability, but this location does not have access to any abilities.
  
     13 | dialog = Ask.provide 'zoot '("Awesome number: " ++ Nat.toText Ask.ask ++ "!")
  

```