code: def setContentLen(self, content, len):
          
          libxml2mod.xmlNodeSetContentLen(self._o, content, len)
docs: Replace the content of a node. NOTE: @content is supposed
            to be a piece of XML CDATA, so it allows entity references,
            but XML special chars need to be escaped first by using
             xmlEncodeEntitiesReentrant() resp. xmlEncodeSpecialChars().