public function __construct($children = null)
{
if ($children instanceof FieldList) {
$this->children = $children;
} elseif (is_array($children)) {
$this->children = new FieldList($children);
} else {
//filter out null/empty items
$children = array_filter(func_get_args());
$this->children = new FieldList($children);
}
$this->children->setContainerField($this);
parent::__construct(null, false);
}