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.

def newEntity(self, name, type, ExternalID, SystemID, content):
        """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. """
        ret = libxml2mod.xmlNewEntity(self._o, name, type, ExternalID, SystemID, content)
        if ret is None:raise treeError('xmlNewEntity() failed')
        __tmp = xmlEntity(_obj=ret)
        return __tmp