Python Org babel Async execution

[Geegee]

The current behavior is that if I run a source code block in org babel python
emacs completely hangs. I am not sure if this is the default behavior or
some misconfiguration on my side so I would like to hear if someone
knows more in this regard. Maybe I could also send the blocks to another
terminal or shell process might also be a work around for me.

[fnussbaum]

By default, the babel blocks run synchronously. The following should run asynchronously:

#+begin_src python :session :async
import time
time.sleep(5)
42
#+end_src