Find and kill child processes of a process.

    :param pid: PID of parent process (process ID)
    :return: Nothing

def kill_process_children(pid):
    """Find and kill child processes of a process.

    :param pid: PID of parent process (process ID)
    :return: Nothing
    """
    if sys.platform == "darwin":
        kill_process_children_osx(pid)
    elif sys.platform == "linux":
        kill_process_children_unix(pid)
    else:
        pass