def bin_days_below_above(df):
    """Bins the days below and above features into 4 bins"""
    df_eng = df.copy()

    df_eng["freezing_days"] = df_eng["days_below_0F"] + df_eng["days_below_10F"]
    df_eng["cold_days"] = df_eng["days_below_20F"] + df_eng["days_below_30F"]
    df_eng["warm_days"] = df_eng["days_above_80F"] + df_eng["days_above_90F"]
    df_eng["hot_days"] = df_eng["days_above_100F"] + df_eng["days_above_110F"]

    return df_eng