# Merx::taxRule()

> Gets the tax rule by its key

- Source: `src/Merx.php#L716` <https://github.com/wagnerwagner/merx/blob/2.0.0-alpha.11/src/Merx.php#L716>

```php
Merx::taxRule(null|string $key): null|Wagnerwagner\Merx\TaxRule
```

## Parameters

| Name | Type | Default |
| --- | --- | --- |
| `$key` | `null\|string` | `–` |

## Return type

`null|Wagnerwagner\Merx\TaxRule`

## Parent class

`Wagnerwagner\Merx\Merx`