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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 renew(self):
 """ Renew the lock if acquired. """

        if self.token is not None:
            try:
                self.client.test_and_set(self.key, self.token, self.token, ttl=self.ttl)
                return True
            except ValueError, e:
                self.token = None
                return False