code: def _check_initialized(self):
      
      baddies = self._find_uninitialized()
      if baddies:
        raise datastore_errors.BadValueError(
            'Entity has uninitialized properties: %s' % ', '.join(baddies))
docs: Internal helper to check for uninitialized properties.
  
      Raises:
        BadValueError if it finds any.