def renew(self, session_id, dc=None):
            """
            This is used with sessions that have a TTL, and it extends the
            expiration by the TTL.

            *dc* is the optional datacenter that you wish to communicate with.
            If None is provided, defaults to the agent's datacenter.

            Returns the session.
            """
            params = {}
            dc = dc or self.agent.dc
            if dc:
                params['dc'] = dc
            return self.agent.http.put(
                callback(is_json=True, one=True, allow_404=False),
                '/v1/session/renew/%s' % session_id, params=params)
dataset/ETHPy150Open cablehead/python-consul/consul/base.py/Consul.Session.renew/original