public function popEntries($number)
    {
        if (count($this) < $number) {
            $count = count($this);

            throw new SwatException(
                printf(
                    'Unable to pop %s entries. NavBar ' .
                        'only contains %s entries.',
                    $number,
                    $count
                )
            );
        } else {
            return array_splice($this->entries, -$number);
        }
    }