Import error web "no module named web"

I did an web application using web.py and after a while I realize that my python compiler was configure to use python2 instead of python3 (both are installed). With python2 my application was working but I got string in unicode so I try to execute my code using python3:

python3 mycode.py

But I get different kind of error, the lib urlparse was not found (this problem was cause by a new name in python3 which is urllib) but I got a problem with:

import web

The return error is:

ImportError: No module named 'web'

I can't figure out where the problem come from.