This is exactly what I thought when I started running commands. The "interpreter" is so incredibly slow. Then I looked at the source code and just face-palmed. Python?? Really?
The problem with the approach taken is that it compiles everything you ever typed every time you type something. I honestly can't think of a worse combination. C++ is the language, you need a Python interpreter to run it. And there's no incremental compilation, so it just gets slower and slower the more you do.
People who write stuff in Python need to realise that sometimes you can't solve a problem just by wrapping something in Python. Occasionally you need to do some actual work. I'm afraid I see this all too often.