Question: what is in the center of the milky way galaxy
[{'answer': 'a supermassive black hole', 'provenance': [{'wikipedia_id': '373352', 'title': 'Galactic Center', 'start_paragraph_id': 18, 'start_character': 222, 'end_paragraph_id': 18, 'end_character': 247, 'bleu_score': 1.0, 'section': 'Section::::Supermassive black hole.\n'}]}]