code: public function sort() {
  		$this->uasort(function($a, $b) {
  			$priority_a = (int) $a->get('priority') ? : 500;
  			$priority_b = (int) $b->get('priority') ? : 500;
  			if ($priority_a == $priority_b) {
  				return 0;
  			}
  			return ($priority_a < $priority_b) ? -1 : 1;
  		});
  		return $this;
  	}
docs: Sort by priority
  @return self