def process_res_df(df, ind, trans_res):
    """handle if a transformer returns multiple columns
    To manage this, we just add the name of column in a clean
    way, removing periods and lowercasing it.

    Parameters
    ----------
    df, dataframe, current dataframe
    ind, indicator object
    trans_res, result from the transformer function

    Returns
    -------
    df, dataframe, updated dataframe with the new columns
    """
    for key in trans_res.keys().values:
        i_name = ind.get("name")
        clean_key = key.lower()
        clean_key = clean_key.replace(".", "")
        clean_key = clean_key.replace(" ", "_")
        df_key = f"{i_name}_{clean_key}"
        df[df_key] = trans_res[key]

    return df