how to make a python file run in the background

1> pythonw script.py

1def check_process():
2    import subprocess
3    script_name = "test.py"
4    cmd='pgrep -f .*python.*{}'.format(script_name)
5    process = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
6    my_pid, err = process.communicate()
7    if len(my_pid.splitlines()) >0:
8        print("Script Running in background")
9        sys.exit(0);
10check_process()

1#Cmd
2C:\..\>cd DIRECTORY
3C:\..\DIRECTORY>pythonw python.py
4#Close in Task Manager