def METHOD_NAME(
    self,
    obs_keys: List[str],
    index_lists: Optional[List[List[Union[int, datetime]]]] = None,
) -> pd.DataFrame:
    if index_lists is None or all(index_list is None for index_list in index_lists):
        return self.data
    names = self.data.columns.get_level_values(0)
    data_index = self.data.columns.get_level_values("key_index")
    cond = self._create_condition(names, data_index, obs_keys, index_lists)
    return self.data.iloc[:, cond]