This is a configuration file maintained by the Python project which optimizes (g)vim for writing Python code. You don't have to replace your existing .vimrc with it; in fact, it has conditionals that only fire if vim detects that you're editing Python code so it shouldn't mess with anything else you work on. Here's how I use it:
0) Copy this file as ~/.vim/vimrc.python
1) Add the following line to ~/.vimrc:
Uncomment automatic indentation at the end of the file, otherwise this file won't do much for you. I also uncommented syntax highlighting.