How to use anonymous function to create new object

invoke.php

<?php

class Toto
{
    private $foo;

    public function __construct($foo)
    {
        $this->setFoo($foo);
    }

    public function getFoo()
    {
        return $this->foo;
    }

    public function setFoo($foo)
    {
        $this->foo = $foo;

        return $this;
    }
}

class Collection
{
    private $data = [];

    public function set($key, $value)
    {
        $this->data[$key] = $value;
    }

    public function get($key)
    {
        return $this->data[$key];
    }
}
echo '<pre>', PHP_EOL;

//BAD USE ... 
$collection = new Collection;
$collection->set('foo', new Toto('bar'));

echo $collection->get('foo')->getFoo(), PHP_EOL; //bar;
$foo = $collection->get('foo');
$foo->setFoo('baz');
echo $collection->get('foo')->getFoo(), PHP_EOL; //baz;


//IMPROVE USE THANKS TO MAGIC __invoke
$collection->set('toto', function () {
    return new Toto('bar');
});

echo $collection->get('toto')->__invoke()->getFoo(), PHP_EOL; //bar;
$toto = $collection->get('toto')->__invoke();

$toto->setFoo('baz');
echo $toto->getFoo(), PHP_EOL; //baz

echo $collection->get('toto')->__invoke()->getFoo(), PHP_EOL; //bar;

//coool tu instancie 1 nouvelle object à chaque fois mais tu dois des fois
// explicitement utiliser __invoke;