<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def pid(self):
 """Get the pid which represents a daemonized process. The result should be None if the process is not running. """

        try:

            with open(self.pidfile, 'r') as pidfile:

                try:

                    pid = int(pidfile.read().strip())

                except ValueError:

                    return None

                try:

                    os.kill(pid, 0)

                except OSError as e:

                    if e.errno == errno.EPERM:

                        return pid

                    elif e.errno == errno.ESRCH:

                        return None

                    LOG.exception(
                        "os.kill returned unhandled error "
                        "{0}".format(e.strerror)
                    )
                    sys.exit(exit.PIDFILE_ERROR)

                return pid

        except IOError:

            if not os.path.isfile(self.pidfile):

                return None

            LOG.exception("Failed to read pidfile {0}.".format(self.pidfile))
            sys.exit(exit.PIDFILE_INACCESSIBLE)