Happy day and Happy day and Happy day but Sad minute so Sad minute drats! {('but', 'Sad', 'minute'): ['so'], ('Happy', 'day', 'but'): ['Sad'], ('Sad', 'minute', 'so'): ['Sad'], ('Sad', 'minute', 'drats!'): [''], ('minute', 'so', 'Sad'): ['minute'], ('', '', 'Happy'): ['day'], ('day', 'but', 'Sad'): ['minute'], ('so', 'Sad', 'minute'): ['drats!'], ('and', 'Happy', 'day'): ['and', 'but'], ('Happy', 'day', 'and'): ['Happy', 'Happy'], ('day', 'and', 'Happy'): ['day', 'day'], ('', 'Happy', 'day'): ['and'], ('', '', ''): ['Happy']}