Question: what is the key signature for b flat major
[{'answer': 'has two flats', 'provenance': [{'wikipedia_id': '1969913', 'title': 'B-flat major', 'start_paragraph_id': 1, 'start_character': 115, 'end_paragraph_id': 1, 'end_character': 128, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1969913', 'title': 'B-flat major', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 198, 'bleu_score': 0.6043435435183161, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14138565760561973586}, 'section': 'Section::::Abstract.'}]}]