Hi everyone. I have a cellular automata framework in C++ and I use cython and cpython to run it. I found out that if I port it to pure python and run it with pypy, it's close to the same performance as the C++ version. (about 2x as slow, compared to 20x as slow when using pure python + cpython). When I throw in other overheads with pure python libraries, using the pure python and pypy is much faster than cpython with the C++ library, all things equal. What I'd like to do is detect if pypy or cpython is doing the importing of my module, and switch over to the pure python interface if pypy is found. As it stands I have to do it manually in my module's __init__.py. *Is there any way to detect if my module is being imported by pypy vs cpython?* Either via sys, or maybe some latent variable that is present, or something else. sys.argv[0] only has the script name (obviously), not the interpreter call. Keep up the outstanding work. Pypy is great! Thanks! Blaine