psalm/tests/Config/Plugin/FilePlugin.php

<?php
namespace Psalm\Test\Config\Plugin;

use Psalm\Plugin;
use SimpleXMLElement;

/** @psalm-suppress UnusedClass */
class FilePlugin implements \Psalm\Plugin\PluginEntryPointInterface
{
    /** @return void */
    public function __invoke(Plugin\RegistrationInterface $registration, SimpleXMLElement $config = null)
    {
        require_once __DIR__ . '/Hook/FileProvider.php';

        $registration->registerHooksFromClass(Hook\FileProvider::class);
    }
}