Question: when did coca cola start being called coke
[{'answer': '1941', 'provenance': [{'wikipedia_id': '6690', 'title': 'Coca-Cola', 'start_paragraph_id': 107, 'start_character': 0, 'end_paragraph_id': 107, 'end_character': 4, 'bleu_score': 1.0, 'section': 'Section::::Advertising.\n'}]}, {'provenance': [{'wikipedia_id': '6690', 'title': 'Coca-Cola', 'start_paragraph_id': 107, 'start_character': 0, 'end_paragraph_id': 107, 'end_character': 303, 'bleu_score': 0.963949056609222, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7786667667661895369}, 'section': 'Section::::Advertising.\n'}]}]