original_string: public function add(string $id_option = null, array $cfg): ?string
    {
      return (
        ($id_option = $this->_get_id_option($id_option)) &&
        $this->_insert($id_option, $cfg)
      ) ? $this->db->last_id() : null;
    }
code: public function add(string $id_option = null, array $cfg): ?string
    {
      return (
        ($id_option = $this->_get_id_option($id_option)) &&
        $this->_insert($id_option, $cfg)
      ) ? $this->db->last_id() : null;
    }
code_tokens: public function add ( string $ id_option = null , array $ cfg ) : ? string { return ( ( $ id_option = $ this -> _get_id_option ( $ id_option ) ) && $ this -> _insert ( $ id_option , $ cfg ) ) ? $ this -> db -> last_id ( ) : null ; }
docstring: Adds a new preference for the given option for the current user.
  
  @param null|string $id_option
  @param array $cfg
  @return null|string
docstring_tokens: Adds a new preference for the given option for the current user .