Is there any convenience method that allows me to concatenate two Doctrine ArrayCollection()? something like:

$collection1 = new ArrayCollection();
$collection2 = new ArrayCollection();

$collection1->add($obj1);
$collection1->add($obj2);
$collection1->add($obj3);

$collection2->add($obj4);
$collection2->add($obj5);
$collection2->add($obj6);

$collection1->concat($collection2);

// $collection1 now contains {$obj1, $obj2, $obj3, $obj4, $obj5, $obj6 }

I just want to know if I can save me iterating over the 2nd collection and adding each element one by one to the 1st collection.

Thanks!