def METHOD_NAME(df: pd.DataFrame, df_add: pd.DataFrame):
    """
    Method used to update aggregate DataFrame on a ticker level.
    :param <pd.DataFrame> df: aggregate DataFrame used to store all tickers.
    :param <pd.DataFrame> df_add: DataFrame with the latest values.
    """
    agg_df_tick = set(df_tickers(df))
    add_df_tick = set(df_tickers(df_add))
    df['ticker'] = df['cid'] + '_' + df['xcat']
    # If the ticker is already defined in the DataFrame, replace with the new series
    # otherwise append the series to the aggregate DataFrame.
    df = df[~df['ticker'].isin(list(agg_df_tick.intersection(add_df_tick)))]
    df = pd.concat([df, df_add], axis=0,
                   ignore_index=True)
    df = df.drop(['ticker'], axis=1)
    return df.sort_values(['xcat', 'cid', 'real_date'])