code: def saveFileTo(self, buf, encoding):
          
          if buf is None: buf__o = None
          else: buf__o = buf._o
          ret = libxml2mod.xmlSaveFileTo(buf__o, self._o, encoding)
          return ret
docs: Dump an XML document to an I/O buffer. Warning ! This call
            xmlOutputBufferClose() on buf which is not available after
             this call.