public function dasherize() 
    {
        $this->data = preg_replace("/[^a-zA-Z0-9_\-\s]/i", '', $this->data);
        $this->data = str_replace(' ', '-', trim($this->data));
        $this->data = preg_replace("/-+/i", '-', $this->data);
        $this->data = strtolower($this->data);

        return $this;
    }