<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def execute(self, peer_jid, command_name):
 """ Start execution of a command with a peer. :param peer_jid: JID of the peer to start the command at. :type peer_jid: :class:`~aioxmpp.JID` :param command_name: Node name of the command to execute. :type command_name: :class:`str` :rtype: :class:`~.adhoc.service.ClientSession` :return: A started command execution session. Initialises a client session and starts execution of the command. The session is returned. This may raise any exception which may be raised by :meth:`~.adhoc.service.ClientSession.start`. """


        session = ClientSession(
            self.client.stream,
            peer_jid,
            command_name,
        )
        yield from session.start()
        return session