CachedContainerFIle

<?php

class CachedContainer extends Container
{
    protected $container;

    public function __construct()
    {
        $this->container['foo'] = new Bar();
        $this->container['bar'] = new Foo();
    }
}

Container

<?php

class SymfonyContainer
{
    public function getContainer()
    {
        $container = new Container();
        $container->add('foo', $this->get('bar'));
        $container->add('bar', $this->get('foo'));
        
        return $container;
    }