/**
* Add a child to this container.
*
* @param BlockInterface $child
* @param string $key the collection index name to use in the
* child collection. if not set, the child
* will simply be appended at the end.
*
* @return bool Always true
*/
public function addChild(BlockInterface $child, $key = null)
{
if ($key != null) {
$this->children->set($key, $child);
return true;
}
return $this->children->add($child);
}
