B. Сложная подкрутка_1

def change_price(group):
    mean = group['UnitPrice'].mean()
    min_p = group['UnitPrice'].min()

    bad = group.assign(
        UnitPrice=group['UnitPrice']*2,
        Country=group['Country']+'_bad_times'
    )
    great = group.assign(
        UnitPrice=np.maximum(min_p, group['UnitPrice']-0.15*mean),
        Country=group['Country']+'_great_times'
    )
    return pd.concat([bad, great], ignore_index=True)