Question: who convened the second council of constantinople in 553
[{'answer': 'Emperor Justinian I', 'provenance': [{'wikipedia_id': '48808', 'title': 'Second Council of Constantinople', 'start_paragraph_id': 1, 'start_character': 452, 'end_paragraph_id': 1, 'end_character': 471, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]