Internal definitions are recommended instead of `let` expressions, to reduce nesting.

Nested `when` expressions can be merged into a single compound `when` expression.

The `provide/contract` form is a legacy form made obsolete by `contract-out`.

Use `make-temporary-directory` to make directories instead of `make-temporary-file`.

This `and` expression's result is ignored. Using `when` makes this clearer.

Add an explicit `[else (void)]` clause to make the default behavior clear.

Internal definitions are recommended instead of `let` expressions, to reduce nesting.

Internal definitions are recommended instead of `let` expressions, to reduce nesting.