code: func CheckVersion(ver string) error {
  	compat, err := version.Compatible(ver)
  	if err != nil {
  		return err
  	}
  	if !compat {
  		return fmt.Errorf("version mismatch: using goagen %s to generate code that compiles with goa %s",
  			ver, version.String())
  	}
  	return nil
  }
docs: // CheckVersion returns an error if the ver is empty, contains an incorrect value or
  // a version number that is not compatible with the version of this repo.