SQLObject.select appears to generates bogus SQL if an empty string is passed as the first arg

In the BugSet.searchAsUser update that I'm about to submit to pqm, there's some code like this:

        if where_clauses:
            return Bug.select(
                ' AND '.join(where_clauses), **other_params)
        else:
            return Bug.select(**other_params)

which works as expected (i.e. bug.txt passes.) But changing that to:

        return Bug.select("", **other_params)

causes exception output like:

...
    ProgrammingError: ERROR: syntax error at end of input at character 32

    SELECT COUNT(*) FROM Bug WHERE
...

when running the bug.txt test.

Instead, I would have expected my tests to fail (because I've changed the behaviour to have empty filter criteria), but not raise ProgrammingError exceptions.