code: func FailOnError(err error) {
  	if merr, ok := err.(MultiError); ok {
  		if len(merr) == 0 {
  			return
  		}
  		fmt.Fprintf(os.Stderr, merr.Error())
  		os.Exit(1)
  	}
  	if err != nil {
  		fmt.Fprintf(os.Stderr, err.Error())
  		os.Exit(1)
  	}
  }
docs: // FailOnError will exit with code 1 if `err != nil`. This function
  // will handle properly the MultiError this dslengine provides.