Question: who sang gonna sit right down and write myself a letter
[{'answer': 'Fats Waller', 'provenance': [{'wikipedia_id': '3444104', 'title': "I'm Gonna Sit Right Down and Write Myself a Letter", 'start_paragraph_id': 1, 'start_character': 243, 'end_paragraph_id': 1, 'end_character': 254, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3444104', 'title': "I'm Gonna Sit Right Down and Write Myself a Letter", 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8676900974977413900}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3444104', 'title': "I'm Gonna Sit Right Down and Write Myself a Letter", 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 305, 'bleu_score': 0.96746874041754, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8676900974977413900}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3444104', 'title': "I'm Gonna Sit Right Down and Write Myself a Letter", 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['It was popularized by Fats Waller, who recorded it in 1935 at the height of his fame.', '"I\'m Gonna Sit Right Down and Write Myself a Letter" is a 1935 popular song with music by Fred E. Ahlert and lyrics by Joe Young. It has been recorded many times, and has become a standard of the Great American Songbook.']}}]}]