code: def transform(self, key, xml, **kwargs):
          
          if key in self._xsltLibrary and self.gateway_connected() and key in self._converters:
              return self._converters[key].transform(xml, self._parms(**kwargs))
          return None
docs: Transform the supplied XML using the transform identified by key
          @param key: name of the transform to apply
          @param xml: XML to transform
          @param kwargs: XSLT parameters
          @return: Transform output or None if transform failed