Question: who led the revolt of 1857 in kanpur
[{'answer': 'Nana Sahib', 'provenance': [{'wikipedia_id': '774156', 'title': 'Nana Sahib', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 10, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '774156', 'title': 'Nana Sahib', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 887, 'bleu_score': 0.8780241337388921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10066509206241948740}, 'section': 'Section::::Abstract.'}]}]