def _to_pairs(self, ignore=None, for_update=True):
result = Base._to_pairs(self, ignore)
if for_update is True:
result['_version'] = self._version_
result['_version_by'] = self._version_by_
result['_version_on'] = self._version_on_
return result
def _from_pairs(self, pairs):
if self._version_ != 0 and pairs.get('_version') != self._version_:
raise Exception('Version mismatch')
Base._from_pairs(self, pairs)
