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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 uid(self):
 """uid is now generated automatically according to the claims. This should actually only be used for cookie generation """

        exp = datetime.datetime.utcnow() + self.expDelay
        claims = {
            'user_info': self.user_info,
            # Note that we use JWT standard 'exp' field to implement session expiration
            # we completely bypass twisted.web session expiration mechanisms
            'exp': calendar.timegm(datetime.datetime.timetuple(exp))}

        return jwt.encode(claims, self.site.session_secret, algorithm=SESSION_SECRET_ALGORITHM)