Can Python on Google App Engine act as an FTP server (FTP TLS) or sFTP client?

Despite several posts on StackOverflow suggesting Google App Engine not support FTP with Python, FTP is now working. (We've posted a working sample code here .)

Given GAE's progress with basic FTP, has anyone found a way for a Google App Engine script to serve an sFTP or FTPS (FTP TLS) client?