code: @Override
  	public boolean detach(Attachment attachment) {
  		boolean found=this.attachments.containsValue(attachment);
  		if(found) {
  			AttachmentId remove = this.attachmentsById.remove(attachment.id());
  			this.attachmentsByResourceId.remove(attachment.resourceId());
  			this.attachments.remove(remove);
  		}
  		return found;
  	}
docs: {@inheritDoc}