How can i use aysncio with subprocess in python to run commands on multiple boxes without waiting for subprocess to return output for each box?

Here is the snippet of my code. i want to start up the app on server A, then go B and then to C without waiting on the output from A.

import subprocess 
machine_list = ["A","B","C"]  

def start(machine):  
    start_cmd = "/home/users/start.sh"  
    start_process_status = subprocess.Popen(start_cmd,
    stdout=subprocess.PIPE, stdin=subprocess.PIPE, universal_newlines=True, shell=True)  
    output, errors = start_process_status.communicate()
    output = output.split("\n")  
    print("Start app output on {} : {} ".format(machine, output))  

for machine in machine_map:  
    start(machine)