Your problem space is underspecified. Is this for a command-line app? Is this code supposed to be used as a library?
In addition to the two other answers, you could embed the code into a binary. When it starts, decode the code and eval the string. This works for a shared library extension as well. You could also do that with byte code, I think, but it wouldn't be as simple as calling Py_EvalCode.
py2exe or freeze are other solution, which convert the code into an executable. It just includes the code in the binary, and doesn't do any sort of serious obsfucation, but it's still harder than opening a .py file.
You could write the code in Cython, which is similar to Python and writes Python extension files in C, for use as a .so. That's perhaps the hardest of these to reverse engineer and still give you a high-level language for develoment.
They are all hackable, as are all solutions. How hard to you want it to be?