/**
  * Main g_tool_tips Instance
  *
  * Ensures only one instance of g_tool_tips is loaded or can be loaded.
  *
  * @since 1.0.0
  * @static
  * @see g_tool_tips()
  * @return Main g_tool_tips instance
  */
 public static function instance($file = '', $version = '1.0.0')
 {
     if (is_null(self::$_instance)) {
         self::$_instance = new self($file, $version);
     }
     return self::$_instance;
 }