Assuming the .env file is loaded before execution, how can you append to it without overriding it?

DEBUG=True
FOO=BAR
PYTHONPATH="/Users/James/project/"

The above file would (?) override it, and that would be bad. I could put it in .bash_profile or .profile, but that's not consistent with what I have now, and I only want to set it for the current virtualenv too.

I don't think this makes any difference, but I'm using Mac OS X (the tutorial I was using was multi-platform)