public function slice($offset, $length = null)
    {
        $array = [];
        
        foreach ($this->collection->slice($offset, $length) as $element) {
            $array[$this->getKey($element)] = $element;
        }
        
        return $array;
    }
public function slice($offset, $length = null)
    {
        $array = [];
        
        foreach ($this->collection->slice($offset, $length) as $element) {
            $array[$this->getKey($element)] = $element;
        }
        
        return $array;
    }
{@inheritDoc}