Question: when did the iphone 4 first come out
[{'answer': 'June 7 , 2010', 'provenance': [{'wikipedia_id': '23501895', 'title': 'IPhone 4', 'start_paragraph_id': 6, 'start_character': 49, 'end_paragraph_id': 6, 'end_character': 62, 'bleu_score': 1.0, 'section': 'Section::::History.:Prototypes.\n'}]}, {'provenance': [{'wikipedia_id': '23501895', 'title': 'IPhone 4', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 396, 'bleu_score': 0.866226661788252, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7454451931278999810}, 'section': 'Section::::Abstract.'}]}]