@abc.abstractmethod<EOL><INDENT>def get_effective_agent_id(self):<DEDENT>
return<EOL>
Gets the ``Id`` of the effective agent in use by this session.

        If ``is_authenticated()`` is true, then the effective agent may
        be the same as the agent returned by
        ``getAuthenticatedAgent()``. If ``is_authenticated()`` is
        ``false,`` then the effective agent may be a default agent used
        for authorization by an unknwon or anonymous user.

        :return: the effective agent
        :rtype: ``osid.id.Id``


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