[Zope] calling a SQL method without arguments

[Daniel M. Drucker]

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?