Didn't they mention in the B2 announcement discussion that there's a linux client for that? Or, more accurately, it's a python library used by a simple python CLI?
I just found this[1], which looks like what you want. It's not a library, but it is only 245 lines of python, so I doubt it's that complex.
We've got that coming up with Backblaze B2, we have APIs and CLIs that you'll be able to use for Linux builds and servers! If you go to: https://www.backblaze.com/b2/docs/ you can read our docs!
From afar it looks very compelling, but unfortunately I can't use it, because no Linux :(