def visit_empty_set_expr(self, element_types):
    return ('SELECT %s FROM (SELECT %s) WHERE 1!=1' % (', '.join(('1' for type_ in (element_types or [INTEGER()]))), ', '.join(('1' for type_ in (element_types or [INTEGER()])))))
def visit_empty_set_expr(self, element_types):
    return ('SELECT %s FROM (SELECT %s) WHERE 1!=1' % (', '.join(('1' for type_ in (element_types or [INTEGER()]))), ', '.join(('1' for type_ in (element_types or [INTEGER()])))))