[Zope] Folder property with dtml

I want to test for a value of a folder property to conditionally include css in a css.dtml instead of putting a condition on the whole css file in zpt or adding additional css to unstyle and restyle in some classes in same skin. Something like this... <dtml-if 'here.my_property == some_value'> some css here ... <dtml-if> Can someone advise of a way of getting property for comparison directly without having to write a script python to return context.my_property. I have to say I really only use dtml for zsql so it is a bit foreign compared to ZPT. I could not find anything in Zope book about getting a folder property without knowing the folder name first. Regards David