# assert_null · Rell standard library · Chromia Docs (concept)

> pure function assert_ null(actual: anything): unit Assert a value is null . Parameters actual — the value Since 0.10.4

Source: https://docs.chromia.com/pages/rell-stdlib/-rell-system-library/rell.test/assert_null/

FUNCTION

# assert\_null

```signature
pure function assert_null(actual: anything): unit
```

Assert a value is `null`.

**Parameters**

* **actual** — the value

Since 0.10.4

[View this page on docs.chromia.com](https://docs.chromia.com/pages/rell-stdlib/-rell%20-system%20-library/rell.test/assert_null.html)Generated API reference, mirrored from the live docs