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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def valid_lock(self):
 """ See if the lock exists and is left over from an old process. """


        lock_pid = self.get_lock_pid()

        # If we're unable to get lock_pid
        if lock_pid is None:
            return False

        # this is our process
        if self._pid == lock_pid:
            return True

        # it is/was another process
        # see if it is running
        try:
            os.kill(lock_pid, 0)
        except OSError:
            self.release()
            return False

        # it is running
        return True