The email package has two files to help it maintain compatibility with Python 2.1 and Python 2.2+. There's a _compat21.py and a _compat22.py that contains tricky bits that are different between the two Python versions. Other code that needs something out of these modules, first tries to import _compat22.py, wrapping this import so that if errors occur, it backs down to _compat21.py. The problem comes when I do "python2.1 setup.py install", which tries to bytecompile all the .py files. Naturally Python 2.1 won't be able to compile _compat22.py and indeed you get a SyntaxError. Is there a way -- in my setup.py -- that I can first detected which Python version I'm using (should be easy), and then skip byte compilation of _compat22.py when I find I'm using Python 2.1? Thanks, -Barry