1) CPython is written in portable readable C code. 2) CPython has been around since 1991, and thus people have had the time to port it properly. 3) Python have

1) CPython is written in portable readable C code. 2) CPython has been around since 1991, and thus people have had the time to port it properly. 3) Python have shown an interest in supporting both Unix and Windows for a long time (and later OS X), thus every new change has to describe how it will interact with both systems. You as an python developer don't have to worry much about different platforms since every new library and language feature tries to work the same on all supported platforms. (of course this doesn't always happen)