Check if a process exists with a given pid in Python

import psutil
pid = 12345
if psutil.pid_exists(pid):
    print("a process with pid %d exists" % pid)
else:
    print("a process with pid %d does not exist" % pid)

References
https://stackoverflow.com/questions/568271/how-to-check-if-there-exists-a-process-with-a-given-pid-in-python