Python script does not restart after it crashes

I have a python script that is doing some stuff called "python1.py". Sometimes because connection issue, it crashes. I have another script called "loop.py" that is supposed to monitor the first one when it crashes and restart it. So far, it fails to restart. Meaning, when an exception is risen ( IOError or WatsonException ( I am using a Watson API ) ) the script stops

python1.py is something like this :

def mainfunction ():
    a = randrange(0, 1)
    Print (' my routine is doing something')
    if a = 1 :
        Print ('a = 1 ')
    else :
        Print (' a is not equals to 1') 

mainfunction ()

The other script that is supposed to restart the first one is something like this :

def loopApp():
    while True :
        try:
            python1.mainfunction ()
        except IOError :
            print (' IOError y')
        except WatsonException :
            print (' Exception from watson API')

loopApp ()

python1.py should restart when every time the exceptions happens, but it is not.

I found the way using python subprocess. It works fine and I could get expections working.

def loopApp():
   
    loop = 1
    while loop == 1:
        print ("wa_loop is starting")
        try:
            process = subprocess.call(['python', 'wa_dir_watch.py'])
        except 'IOError':
            print ("\nretrying after IOError")
            continue         
        except KeyboardInterrupt:
            print ("\nstopped by user Ctr+C")
            quit() 
            
loopApp()