@abc.abstractmethod<EOL><INDENT>def get_authenticated_agent_id(self):<DEDENT>
return<EOL>
Gets the ``Id`` of the agent authenticated to this session.

        This is the agent for which credentials are used either acquired
        natively or via an ``OsidProxyManager``.

        :return: the authenticated agent ``Id``
        :rtype: ``osid.id.Id``
        :raise: ``IllegalState`` -- ``is_authenticated()`` is ``false``

        *compliance: mandatory -- This method must be implemented.*