How to execute processes at the same time for multi web user application

I am using a python socketio async server. I have several processes that can occur in my backend. Each user in my website can send a socket to the backend and execute their own process however, in my terminal, each users process is executing one at a time.

For example:

async def trainit(sid,data,code): 

my trainmodel function is running one at a time, however I want every process to run in parallel.

Let us start with operating system, go over to python and then come back to socketio.

With your question in mind I would think of parent process and child processes if ever.

I assume python socketio can not go above what is possible within operating system itself.

I found a fine discussion including python samples here:
Is there a way for multiple processes to share a listening socket?

Python Docs Multiprocessing

Search within python socketio docs on multiple processes

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