Best Git library for Python?

[Dun Peal]

Hi folks,

I'm writing a Python program to operate on Git repositories.

The program works at the user level of abstraction: i.e. it needs to
do everything that an end user can do with Git.

I'm talking about the high-level commands like git-clone, git-branch,
git-fetch, git-merge, git-rebase, git-push.

Having lower-level functionality would be nice, but not essential.

What is essential is reliability: the library should work correctly
even under reasonable load, and fail noisily and predictably in the
extreme situations that simply can't be handled correctly.

What's the best library to use?

Thanks, D