Question: when was the yellow jersey introduced to the tour de france
[{'answer': '1919', 'provenance': [{'wikipedia_id': '277780', 'title': 'General classification in the Tour de France', 'start_paragraph_id': 1, 'start_character': 136, 'end_paragraph_id': 1, 'end_character': 140, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '277780', 'title': 'General classification in the Tour de France', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 206, 'bleu_score': 0.79728520257501, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12903715296259078019}, 'section': 'Section::::Abstract.'}]}]