def _encode_relation(self, name):
        '''(INTERNAL) Decodes a relation line.

        The relation declaration is a line with the format ``@RELATION
        <relation-name>``, where ``relation-name`` is a string.

        :param name: a string.
        :return: a string with the encoded relation declaration.
        '''
        for char in ' %{},':
            if char in name:
                name = '"%s"'%name
                break

        return u'%s %s'%(_TK_RELATION, name)
(INTERNAL) Decodes a relation line.

        The relation declaration is a line with the format ``@RELATION
        <relation-name>``, where ``relation-name`` is a string.

        :param name: a string.
        :return: a string with the encoded relation declaration.