containercollection.php

См. документацию.

<?php
namespace Bitrix\Main\Copy;
 
use Bitrix\Main\Type\Dictionary;

class ContainerCollection extends Dictionary
{
    protected function addContainer(Container $container, $offset = null)
    {
        parent::offsetSet($offset, $container);
    }
 
    public function offsetSet($offset, $value)
    {
        $this->addContainer($value, $offset);
    }
}