private function find_parent_currencies(TreeObject $object = null)
{
//Traverses back the tree to the head seaching by parent
//and correctly populates the rates array.
if ($object->has_parents()) {
$this->find_in_rates_array($object->get_parent()->get_value(), $object->get_value());
$this->find_parent_currencies($object->get_parent());
}
}
