Question: who sings war don't let me down
[{'answer': 'American production duo The Chainsmokers', 'provenance': [{'wikipedia_id': '49517487', 'title': "Don't Let Me Down (The Chainsmokers song)", 'start_paragraph_id': 1, 'start_character': 33, 'end_paragraph_id': 1, 'end_character': 73, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'vocals of American singer Daya', 'provenance': [{'wikipedia_id': '49517487', 'title': "Don't Let Me Down (The Chainsmokers song)", 'start_paragraph_id': 1, 'start_character': 97, 'end_paragraph_id': 1, 'end_character': 127, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '49517487', 'title': "Don't Let Me Down (The Chainsmokers song)", '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': 3730315981755913292}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '49517487', 'title': "Don't Let Me Down (The Chainsmokers song)", 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 360, 'bleu_score': 0.9684940092844061, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3730315981755913292}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '49517487', 'title': "Don't Let Me Down (The Chainsmokers song)", 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['"Don\'t Let Me Down" is a song by American production duo The Chainsmokers. The song features the vocals of American singer Daya, and was released on February 5, 2016, through Disruptor Records and Columbia Records.', 'Don\'t Let Me Down" is a song by American production duo The Chainsmokers. The song features the vocals of American singer Daya, and was released on February 5, 2016, through Disruptor Records and Columbia Records']}}]}]