def filter_headline(df, non_disaggregation_columns):
    """Given a dataframe filter it down to just the headline data.

    In the case of multiple units it will keep all headline for each unit.
    """

    special_cols = [col for col in non_disaggregation_columns if col in df.columns]

    # Select the non-data rows and filter rows that are all missing (nan)
    disag = df.drop(special_cols, axis=1)
    headline_rows = disag.isnull().all(axis=1)

    headline = df.filter(special_cols, axis=1)[headline_rows]

    return headline