Question: when did why don't we became a band
[{'answer': 'September 27 , 2016', 'provenance': [{'wikipedia_id': '54275432', 'title': "Why Don't We", 'start_paragraph_id': 4, 'start_character': 30, 'end_paragraph_id': 4, 'end_character': 49, 'bleu_score': 1.0, 'section': 'Section::::Career.:2016–present.\n'}]}]