Question: when did the warlocks become the grateful dead
[{'answer': 'December 4 , 1965', 'provenance': [{'wikipedia_id': '12542', 'title': 'Grateful Dead', 'start_paragraph_id': 5, 'start_character': 535, 'end_paragraph_id': 5, 'end_character': 552, 'bleu_score': 1.0, 'section': 'Section::::Formation (1965–1966).\n'}]}, {'provenance': [{'wikipedia_id': '12542', 'title': 'Grateful Dead', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 879, 'bleu_score': 0.6403081580366511, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1391619186830051863}, 'section': 'Section::::Formation (1965–1966).\n'}]}]