How to compare two directories?

[could ildg]

I want to compare 2 directories,
and find If all of theire sub-folders and files and sub-files are identical.
If not the same, I want know which files or folders are not the same.
I know filecmp moudle has cmpfiles function and a class named dircmp,
they may help, but I wonder if there is a ready-to-use function in python libs?
If not, would somebody like to give me some propositions?

Thank you.