public static function key($key, $value = null)
  {
    if ($value == null) return $_SESSION[$key];

    $_SESSION[$key] = $value;
  }
public static function key($key, $value = null)
  {
    if ($value == null) return $_SESSION[$key];

    $_SESSION[$key] = $value;
  }
public static function key ( $ key , $ value = null ) { if ( $ value == null ) return $ _SESSION [ $ key ] ; $ _SESSION [ $ key ] = $ value ; }
Set or get session key

@param mixed $key
@param mixed $value
@return void
Set or get session key