Question: begum akhtar specialised in which form of vocal music
[{'answer': 'Hindustani classical music', 'provenance': [{'wikipedia_id': '1422252', 'title': 'Begum Akhtar', 'start_paragraph_id': 1, 'start_character': 181, 'end_paragraph_id': 1, 'end_character': 207, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1422252', 'title': 'Begum Akhtar', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 207, 'bleu_score': 0.779072280774556, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17502667067185821870}, 'section': 'Section::::Abstract.'}]}]