@abc.abstractmethod<EOL><INDENT>def get_qualifier(self, qualifier_id):<DEDENT>
return<EOL>
Gets the ``Qualifier`` specified by its ``Id``.

        In plenary mode, the exact ``Id`` is found or a ``NotFound``
        results. Otherwise, the returned ``Qualifier`` may have a
        different ``Id`` than requested, such as the case where a
        duplicate ``Id`` was assigned to a ``Qualifier`` and retained
        for compatibility.

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

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