Can't get why php unable to parse this code

class QuestionTagTable extends Doctrine_Table
{
    public function getRelatedTags(array $tags, $limit = sfConfig::get('app_tags_on_sidebar'))
    {
   
    }
}

PHP reports Parse error: syntax error, unexpected '(', expecting ')' on line 

public function getRelatedTags(array $tags, $limit = sfConfig::get('app_tags_on_sidebar'))