code: func IsEmptyConfig(err error) bool {
  	switch t := err.(type) {
  	case errConfigurationInvalid:
  		return len(t) == 1 && t[0] == ErrEmptyConfig
  	}
  	return err == ErrEmptyConfig
  }
docs: // IsEmptyConfig returns true if the provided error indicates the provided configuration
  // is empty.