How to add a para style to a batch of docs?

Hi everyone

I got this script

var docs = app.documents

        for (var i = docs.length-1; i >= 0; i--) {  

            docs[i].paragraphStyles.add({name: “01 Body text”, fontFamily: “Helvetica”, fontStyle:”Light”, pointSize:9, leading:14});

            }

for add paragraph style to docs, but

but Font Family and Font Style not work, can someone tell me why?

Thanks

Regard

Teetan