Emacs Python 3.3 in Ubuntu 13.04 -

how emacs 24 use python 3.3 in ubuntu 13.04?

when used

sudo rm /usr/bin/python sudo ln -s /usr/bin/python3.3 /usr/bin/python 

the apt-get update got in trouble (since apparently depends on python 2.7)

how change emacs?

i tried

(setq py-python-command "python3") suggested on so, did not work either.