[Zope] calling a SQL method without arguments

If I have an SQL method with one optional argument, how can I call it without using that argument: For example: SQL_method Arguments: authorid select * from authors <!--#sqlgroup where--> <!--#sqltest authorid column=authorid type=int optional--> <!--#/sqlgroup--> Theoretically, if I call this with a authorid, it'll return the proper row, and if I don't, it'll return all rows. But, given the following: <!--#in SQL_method--> blah <!--#/in--> I get this error: <!-- Error type: Bad Request Error value: ['authorid'] --> So, what's the proper way to call a SQL method without arguments?