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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 expire(self, secs):
 """ Adds the standard 'exp' field, used to prevent replay attacks. Adds the 'exp' field to the payload. When a request is made, the field says that it should expire at now + `secs` seconds. Of course, this provides no protection unless the server reads and interprets this field. """

        self.add_field('exp',
                lambda req: int(time.time() + secs))