Question: who wrote the song 18 by one direction
[{'answer': 'Ed Sheeran', 'provenance': [{'wikipedia_id': '43771543', 'title': 'Four (One Direction album)', 'start_paragraph_id': 6, 'start_character': 132, 'end_paragraph_id': 6, 'end_character': 142, 'bleu_score': 1.0, 'section': 'Section::::Background and development.\n'}]}, {'provenance': [{'wikipedia_id': '43771543', 'title': 'Four (One Direction album)', 'start_paragraph_id': 6, 'start_character': 0, 'end_paragraph_id': 6, 'end_character': 202, 'bleu_score': 0.948006874591591, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10745963527775571042}, 'section': 'Section::::Background and development.\n'}]}]