Create a file ``/cookbook/security/voter_interface.rst.inc``:

```rst
.. code-block:: php

    interface VoterInterface
    {
        public function supportsAttribute($attribute);
        public function supportsClass($class);
        public function vote(TokenInterface $token, $post, array $attributes);
    }
```

And here you use:

```rst
.. include:: /cookbook/security/voter_interface.rst.inc
```