@abc.abstractmethod<EOL><INDENT>def get_id(self, id_):<DEDENT>
return<EOL>
Gets an ``Id``.

        This method serves to get the principal ``Id`` if the given
        ``Id`` Is an alias.

        :param id: an ``Id``
        :type id: ``osid.id.Id``
        :return: the ``Id``
        :rtype: ``osid.id.Id``
        :raise: ``NotFound`` -- ``id`` is not found
        :raise: ``NullArgument`` -- ``id`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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