[Zope] Using a ZSQL method from a Python script

Hi, I have made a ZSQL method, which adds a line to a table, much like the hire_employee method in 'the Zope book'. When I test it, an html form appears, I can enter all data, submit. I have also implemented the list_all_employees ZSQL method, and when I test it, I can see that in fact the data have landed in the table correctly. So far, so good.

From what I understand in the Zope book, I can then add new employees from a Python script like this:

------------------ context.hire_employee(42,'bob','uncle',50000.00) return "Done" ------------------ I get an internal server error 500, however, when I hit the test button. The hire_employee method and the Python script are in the same folder. What am I overlooking ? Thanks, Marc