code: func MakeAttempt(c context.Context, aid *dm.Attempt_ID) *Attempt {
  	now := clock.Now(c).UTC()
  	return &Attempt{
  		ID:       *aid,
  		Created:  now,
  		Modified: now,
  	}
  }
docs: // MakeAttempt is a convenience function to create a new Attempt model in
  // the NeedsExecution state.