This is work in progress. Not ready for the prime time! Don't try in production!!!

Majority of heavy lifting was done by futurize here.

django-tastypie-mongoengine needs some small fixes. Too bad nobody seems to be caring much about fixing it. It looks like the maintainer chair is open for that project. I just can't get involved there.

Thus far, the front end loads, and is mostly working in Python 2 and some thing are broken in Python 3.
The broken things in Python 3 include:

• from Sample's Tools menu "Add object" form in the tab with XOR search)

Error adding object: ValidationError (Sample:5645181c85db9e828825fe9c) (source.Invalid embedded document instance provided to an EmbeddedDocumentField: ['obj'])

Some services seem to be working too (you've got to use my python3_fixes branch for services)
I've also converted much of the services. I didn't have the patience to convert taxii_service, and stix validator (sdv actually errors out on anything but 2.x), since the libs that they use need to be converted, so I just deleted them for now. I've managed to futurize pytx, but I've got no way of testing.

I've fixed the deletion and crash on uploads, it turned out to be _id that was wrapped into a str().
The tests still fail whether for py2 or py3.

Lots of the bytes <-> str issues can be solved by converting bytes to str by the way of:

if not isinstance(data, str):
       data = data.decode('ISO-8859-1')

I'm not sure how much impact this might have on larger files.