[python] wait process until all subprocess finish?

I have a main process which creates two or more sub processes, I want main process to wait until all sub processes finish their operations and exits?

 # main_script.py

 p1 = subprocess.Popen(['python script1.py']) 
 p2 = subprocess.Popen(['python script2.py'])
 ... 
 #wait main process until both p1, p2 finish
 ...

subprocess.call

Automatically waits , you can also use:

p1.wait()