There is another forums topic with this question that just says no (calls to Python should be sequentialized).
The question was also discussed in the TensorFlow group.
I guess you could do something with Python‘s multiprocessing module (then different Python interpreters are started), but then the elegant and easy possibility to directly call differently Python functions would be gone.
So for me, it is also a „no“. PythonKit is great, but I will start a separate Swift program for each work item / request.