Question: when did the knights of labor start and end
[{'answer': 'December 28 , 1869', 'provenance': [{'wikipedia_id': '17387', 'title': 'Knights of Labor', 'start_paragraph_id': 2, 'start_character': 42, 'end_paragraph_id': 2, 'end_character': 60, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': '1949', 'provenance': [{'wikipedia_id': '17387', 'title': 'Knights of Labor', 'start_paragraph_id': 2, 'start_character': 711, 'end_paragraph_id': 2, 'end_character': 715, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '17387', 'title': 'Knights of Labor', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 778, 'bleu_score': 0.7857067137442161, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8700003742988489241}, 'section': 'Section::::Abstract.'}]}]