How do I inject services in a service?

I am using the following code, but it throws an error.

```php
class RoleNegotiator implements ThemeNegotiatorInterface {

  public static function create(ContainerInterface $interface) {
    return new static(
      $interface->get('router.admin_context')
    );
  }
  public function __construct(RouteMatchInterface $route) {
    $this->route = $route;
  }
}
```