How to call a function declared in the second thread from the first?

Question

Python

I created two threads in one of which listens to the microphone for voice recognition in an infinite loop, and in the second, the GUI is drawn on PYQT5.
Now I need to somehow call the function declared in the second thread from the first one.
o_o how to do it?
I am using Python 3.6, PyQT 5