How to make Subprocess.Popen NOT wait for process completion

I am trying to make an app to run Ark Server exe (Game Server) and be able to gather information from the server as its running but my code stops in its tracks when I open the process using Subprocess.Popen, and will only continue when the process terminates. Example:

def Start():
    server = subprocess.Popen('ArkServer.exe -ArgumentsHere', stdout=subprocess.PIPE, 
                    stdin=subprocess.PIPE, shell=true)

    # Loop or something to read server output

I understand using shell=true can be a big risk but is this context I'm just testing and can fix those types of things later. If anyone can help me be able to run the server and other code simultaneously I would appreciate it.