The docstring for [this commit method](https://github.com/gitpython-developers/GitPython/blob/851beabc93319d8dd05bff211b13d2b35ef097e0/git/index/base.py#L977) references `tree.commit` for documentation on the arguments, but that method doesn't appear to exist. What would be the correct reference, or should the documentation for the arguments just be in this docstring?