Question: when did justin bieber's purpose tour start
[{'answer': 'March 9 , 2016', 'provenance': [{'wikipedia_id': '48529678', 'title': 'Purpose World Tour', 'start_paragraph_id': 14, 'start_character': 47, 'end_paragraph_id': 14, 'end_character': 63, 'bleu_score': 1.0, 'section': 'Section::::Set list.\n'}]}, {'provenance': [{'wikipedia_id': '48529678', 'title': 'Purpose World Tour', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 229, 'bleu_score': 0.8723360571509821, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9537799265736816895}, 'section': 'Section::::Abstract.'}]}]