code: func isAboveMaxDepth(attachmentTimestamp int64) bool {
  	nowMilli := time.Now().UnixNano() / int64(time.Millisecond)
  	return attachmentTimestamp < nowMilli && nowMilli-attachmentTimestamp < maxDepth*milestoneInterval*oneWayDelay
  }
docs: // checks whether by the given timestamp the transaction is to deep to be promoted