Why is Python 3 not backwards compatible?

Python 3.0, compared to 2.6. Python 3.0, also known as “Python 3000” or “Py3K”, is the first ever intentionally backwards incompatible Python release. There are more changes than in a typical release, and more that are important for all Python users. Nevertheless, after digesting the changes, you’ll find that Python really hasn’t changed all that much – by and large, we’re mostly fixing well-known annoyances and warts, and removing a lot of old cruft.

Paramiko’s SSHClient with SFTP

How I can make SFTP transport through SSHClient on the remote server? I have a local host and two remote hosts. Remote hosts are backup server and web server. I need to find on backup server necessary backup file and put it on web server over SFTP. How can I make Paramiko’s SFTP transport work with Paramiko’s SSHClient?

can you add HTTPS functionality to a python flask web server?

I am trying to build a web interface to Mock up a restful interface on networking device this networking device uses Digest Authentication and HTTPS.
I figured out how to integrate Digest Authentication into the web server but I cannot seem to find out how to get https using FLASK if you can show me how please comment on what i would need to do with the code below to make that happen.