parallel-functions/test/Fixture/TestCallables.php

<?php

namespace Amp\ParallelFunctions\Test\Fixture;

class TestCallables
{
    public static function staticMethod(int $value): int
    {
        return $value + 1;
    }

    public function instanceMethod(int $value): int
    {
        return $value + 2;
    }

    public function __invoke(int $value)
    {
        return $value + 3;
    }
}