def WriteMetadata(self, metadata, overwrite=True):
    """Stores "metadata" in the "meta" attribute."""
    if not overwrite and metadata in 'meta':
      raise errors.KeyczarError('"meta" attribute already exists')
    self.dict['meta'] = str(metadata)
dataset/ETHPy150Open viewfinderco/viewfinder/backend/base/keyczar_dict.py/DictWriter.WriteMetadata/swapped operands of `in`