Current state:
216: f.save(branch='master', commit_message='Update testfile')

230: f.save(branch='master', commit_message='Update testfile', encoding='base64')

both of them fail, reporting that branch name is not defined.

For me worked this:

216: f.save(branch_name='master', commit_message='Update testfile')

230: f.save(branch_name='master', commit_message='Update testfile', encoding='base64')

As for the rest - thanks for the job, that you've done :)