@classmethod
def getParentPid(cls, pid):
    """
            getParentPid - Get parent pid of given process pid.

            @param pid <int> - Process pid

            @return <int/None> - Integer of parent pid of @pid, or None if could not determine (like program not running)
        """
    pid = int(pid)
    try:
        statInfo = cls.getStatInfo(pid)
    except:
        return None
    return statInfo['ppid']
