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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 checkTimeout(self, now):
 """Compare current time with last_update time, and raise an exception if we're over the timeout time."""

        log.debug("checking for timeout on session %s", self)
        if now - self.last_update > self.timeout:
            raise TftpTimeout("Timeout waiting for traffic")