[Zope] python call escaping HTML

hello, I'm shure it's a often asked question ... sorry ;o{ How to get python returned string to be not html escaped, just a raw string ? I call a product instance like this : <span tal:replace="python: here.meteo" /> the return value is a html string, and Zope is escaping it like character '<' is rewritting as '<' is there a tal syntax that I can use to tell Zope to not escape python output ??? thanks, Cyrille