[Zope] Calling DTML Document from python script

I got an object 'file' witch contains a DTML Document object. When I try to call it from a pythton script like this : print file() I get the error : Error Type: KeyError Error Value: standard_html_header So what I need to do is to print out the DTML document without it's header and footer (<dtml-var standard_html_header> and <dtml-var standard_html_footer>) and still that it's content get executed (all other dtml-var gets resolved) Anyone knows how to do that and maybe what parameter I have to pass to the print file(...) function?