<?php

/**
 * Your classes should be traversable
 * but you want to let the dev of the
 * interface decide to use Iterator,
 * IteratorAggregate or extending from
 * a traversable class
 */
interface Fooable extends Traversable
{
    public function foo();
}

/**
 * Important order:
 * Fooable needs to be set after another
 * traversable interface
 */
class Foo1 implements IteratorAggregate, Fooable
{
    private $foo;
    
    public function __construct(array $foo = array())
    {
        $this->foo = $foo;
    }
    
    public function foo()
    {
        return 'Foo';
    }
    
    public function getIterator()
    {
        return new ArrayIterator($this->foo);
    }
}

class Foo2 extends ArrayIterator implements Fooable
{
    public function foo()
    {
        return 'Foo';
    }
}

$foo1 = new Foo1(['Foo']);
$foo2 = new Foo2(['Foo']);

foreach ($foo1 as $value) {
    echo $value . PHP_EOL;
}

foreach ($foo2 as $value) {
    echo $value . PHP_EOL;
}

Foo
Foo

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PHP 8.3, Laminas MVC 3.2, Symfony 5.2, Laravel 8.28, PHPUnit 9.5, Doctrine ORM 2.8