code: def addDtdEntity(self, name, type, ExternalID, SystemID, content):
          
          ret = libxml2mod.xmlAddDtdEntity(self._o, name, type, ExternalID, SystemID, content)
          if ret is None:raise treeError('xmlAddDtdEntity() failed')
          __tmp = xmlEntity(_obj=ret)
          return __tmp
docs: Register a new entity for this document DTD external subset.