Not blaming you, since there were people familiar with Python, it's probably good thing to continue using it.
Just thought I'd point out to people that this rewrite was done "last year", which was before Go1 was released march this year. The API was in constant change and it all projects needed constant updating to keep up with weekly releases. (or stick with the r60 with totally different and soon-to-be deprecated API)
The team rewrote from Go to Python for various reasons:
* Tool support (debugging, etc) was supposedly poor
* The standard library wrappers were supposedly buggy
* They had to write a lot of wrappers and libraries themselves
* People on the team were already familiar with Python - after Atlassian's single "Go developer" left, there wasn't much reason to keep it