Calling Julia function from Python Threads runs for forever

I am importing a Python script into my Julia code. I am then trying to call a Julia function within a Multi-threading Python process, which leads to a Deadlock. How can I adapt the Julia Code to be able to call Python with Multi-threading?

My example code:
https://github.com/JulesBlubb/Julia-Multithreading-Problem

System Details:
- Ubuntu 19.10
- Julia 1.3.1 with Pycall v1.91.4
- Python: 3.6.5

Thank you.