I've made a python 3 wrapper for the constant contact restful api (v2). Just letting you know it's out there.
You can check it out the pypi here: https://pypi.python.org/pypi/constant-contact-python/0.1.0
And the github is also here: https://github.com/Blitzen/constant-contact-python
It's still in early dev (Made it last night), but I've tested out a lot of the endpoints successfully.
The only thing which is missing right now is the authentication flow. But if you have the access_token and api_key, the endpoints work.