[Zope] Why can't I subclass a ZSQLMethod?

[Cary O'Brien]

I want to wrap a presentation layer around ZSQLQueries, so that
they will have methods to generate an input form [1] for the query,
and generate tabular results if so desired.

I tried to create a ZClass to do this, but I can't subclass from a
ZSQLMethod.

Any other ideas on how to do this (besides a class where you have
to tell it the ZSQLMethod to use)?

-- cary

[1] Using sql.arguments_str to find out the arguments.  Finding THAT was
    a struggle!