I see what you mean...  Looking at the [current way rake is doing it](https://github.com/edx/edx-platform/blob/master/rakelib/quality.rake#L56),  it's actually installing all of the prereqs, not just the python prereqs, because of the way that prereqs were [deprecated](https://github.com/edx/edx-platform/blob/master/rakelib/prereqs_deprecated.rake#L20).

 Do you think it makes sense to add a task decorator to `install_python_prereqs` in `pavelib/prereqs.py` so that these new paver tasks can just use `@needs('pavelib.prereqs.install_python_prereqs')`?