code: func (j *Job) ValidateRequirements() error {
  	for key, _ := range j.requirements() {
  		if !validRequirements.Contains(key) {
  			return fmt.Errorf("unrecognized requirement in [X-Fleet] section: %q", key)
  		}
  	}
  	return nil
  }
docs: // ValidateRequirements ensures that all options in the [X-Fleet] section of
  // the job's associated unit file are known keys. If not, an error is
  // returned.