code: func handleError(handler func(c *router.Context) error) func(c *router.Context) {
  	return func(c *router.Context) {
  		if err := handler(c); err != nil {
  			ErrorHandler(c, err)
  		}
  	}
  }
docs: // handleError is a wrapper for a handler so that the handler can return an error
  // rather than call ErrorHandler directly.
  // This should be used for handlers that render webpages.