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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 _start_rpc_session(self, sock):
 """Starts a new RPC session with given connection. """

        session_name = RpcSession.NAME_FMT % str(sock.getpeername())
        self._stop_child_activities(session_name)

        rpc_session = RpcSession(sock, self)
        self._spawn_activity(rpc_session)