I am trying to run a code in Ubuntu 20.04, with python 3.8, flask, wsgi and using multiprocessing. I wrote a code that works just fine with python. This is the code:

    from flask import Flask
    from multiprocessing import Process, Manager

    def f(d, l):
        d[1] = '1'
        d['2'] = 2
        d[0.25] = None
        l.reverse()
    # Function to convert   
    def listToString(s):  
        
        # initialize an empty string 
        str1 = " " 
        res = str1.join(list(map(str,s)))
        # return string   
        return res 

    app = Flask(__name__)
    @app.route("/")
    def hello():
        with Manager() as manager:
            d = manager.dict()
            l = manager.list(range(10))

            p = Process(target=f, args=(d, l))
            p.start()
            p.join()

            print(d)
            print(l)    
            return "Hello world! " + listToString(d)
    if __name__ == "__main__":
        app.run()

The problem is when I try to run it using apache 2.4 with the wsgi module. Here is the .conf and .wsgi files:

      <VirtualHost *:80>
           # Add machine's IP address (use ifconfig command)
           ServerName 192.168.0.7

           #Application Configuration. SetEnv command
           SetEnv wsgi.multithread True
           SetEnv wsgi.multiprocess True

           WSGIDaemonProcess testFlask processes=2 threads=15 python-path=/home/israel/server/study:/home/israel/server/env/lib/python3.8/site-packages
           # Give an alias to to start your website url with
           WSGIScriptAlias /testFlask /home/israel/server/study/my_flask_app.wsgi 
           WSGIProcessGroup testFlask

           <Directory /home/israel/server/study/>
                # set permissions as per apache2.conf file  
               <IfVersion < 2.4>
                   Order allow,deny
                   Allow from all
               </IfVersion>
               <IfVersion >= 2.4>
                   Require all granted
               </IfVersion>    
                Options FollowSymLinks
                AllowOverride None
           </Directory>
           ErrorLog ${APACHE_LOG_DIR}/test-error.log
           LogLevel info
           CustomLog ${APACHE_LOG_DIR}/test-access.log combined
      </VirtualHost>

and

    #! /usr/bin/python3.8

    python_home = '/home/israel/server/env'
    activate_this = python_home + '/bin/activate_this.py'
    print("activate dir", activate_this)
    #python 3.8
    exec(open(activate_this).read(), dict(__file__=activate_this))

    import logging
    import sys
    #checking version
    print('systems version {}.{}.{}'.format(sys.version_info[0], sys.version_info[1], sys.version_info[2]))

    sys.path.insert(0, '/home/israel/server/study/')
    from my_flask_app import app as application
    application.secret_key = 'anything you wish'

I use a virtual environment. Through apache and wsgi, the code works fine if I remove the multiprocessing code and also the lines:

      #Application Configuration. SetEnv command
      SetEnv wsgi.multithread True
      SetEnv wsgi.multiprocess True

      WSGIDaemonProcess testFlask processes=2 threads=15 python-path=/home/israel/Documents/Classlol/face_Glasses_Fitting_server-quis/study:/home/israel/Documents/Classlol/face_Glasses_Fitting_server-quis/env/lib/python3.8/site-packages

in the .wsgi file.

When running the former code I get the error: RuntimeError: fork not supported for subinterpreters. I read the documentation an I find nothing. I also check the python 3.8's bug bugzilla.redhat.com/show_bug.cgi?id=1745894 and it seems that it was solved... Its been a week and I got nothing.. Any Ideas?