def to_sql_sequence(self, instring, schema, use_bag_semantics=False):
        """
        Translate a relational algebra string into a list of SQL strings generated
        by a post-order traversal of the parse tree for the input string.

        :param instring: a relational algebra string to translate
        :param schema: a mapping of relation names to their attributes
        :param use_bag_semantics: flag for using relational algebra bag semantics
        :return: a list of SQL translation strings
        """
        root_list = self.to_syntax_tree(instring, schema)
        return [
            sql_translator.translate(root.post_order(), use_bag_semantics)
            for root in root_list
        ]