Question: where does the term pink slip come from
[{'answer': 'most likely originated in vaudeville'}, {'provenance': [{'wikipedia_id': '611343', 'title': 'Termination of employment', 'start_paragraph_id': 25, 'start_character': 0, 'end_paragraph_id': 25, 'end_character': 364, 'bleu_score': 0.9128306541161191, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 459592850736911207}, 'section': 'Section::::Pink slip.\n'}]}]