code: def newEntity(self, name, type, ExternalID, SystemID, content):
          
          ret = libxml2mod.xmlNewEntity(self._o, name, type, ExternalID, SystemID, content)
          if ret is None:raise treeError('xmlNewEntity() failed')
          __tmp = xmlEntity(_obj=ret)
          return __tmp
docs: Create a new entity, this differs from xmlAddDocEntity()
            that if the document is None or has no internal subset
            defined, then an unlinked entity structure will be
            returned, it is then the responsability of the caller to
            link it to the document later or free it when not needed
             anymore.