public function append($items)
    {
        if ($items instanceof static) {
            $items = $items->toArray();
        }
        $this->items = array_merge($this->items, (array)$items);

        return $this;
    }
public function append($items)
    {
        if ($items instanceof static) {
            $items = $items->toArray();
        }
        $this->items = array_merge($this->items, (array)$items);

        return $this;
    }
public function append ( $ items ) { if ( $ items instanceof static ) { $ items = $ items -> toArray ( ) ; } $ this -> items = array_merge ( $ this -> items , ( array ) $ items ) ; return $ this ; }
Append new elements to the list.

@param array|Iterator $items Items to be appended. Existing keys will be overridden with the new values.

@return $this
Append new elements to the list .