Question: when do the arrow and the flash crossover
[{'answer': 'December 2 , 2014', 'provenance': [{'wikipedia_id': '52475215', 'title': 'Flash vs. Arrow', 'start_paragraph_id': 36, 'start_character': 63, 'end_paragraph_id': 36, 'end_character': 80, 'bleu_score': 1.0, 'section': 'Section::::Release.:Broadcast.\n'}]}, {'provenance': [{'wikipedia_id': '52475215', 'title': 'Flash vs. Arrow', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 605, 'bleu_score': 0.9427836745142131, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16470042062606184695}, 'section': 'Section::::Abstract.'}]}]