Append only attribute for directories

I want to create a directory which is undeletable, and that you can only add files, not delete any file therein. I was reading the man chattr page and I came across attribute a >A file with the 'a' attribute set can only be opened in append mode for writing. Only the superuser or a process possessing the CAP_LINUX_IMMUTABLE capability can set or clear this attribute. But it just mentions files. Can I apply it to a directory? Something like sudo chattr +a +u /path/to/dir