# Creating custom rules

Rules consist of two important elements, the model fields and the `test_user` function. They should inherit the `AbstractBaseRule` class from `wagtail_personalisation.rules`.

A simple example of a rule could look something like this:

```python
# From wagtail_personalisation/rules.py

class UserIsLoggedInRule(AbstractBaseRule):
    ...
```

As you can see, the only real requirement is the `test_user` function that will either return `True` or `False` based on the model fields and optionally the request object.

That's it!