Question: what are the main objectives of labor unions
[{'answer': 'improving safety standards'}, {'answer': 'attaining better wages'}, {'answer': 'benefits', 'provenance': [{'wikipedia_id': '17626', 'title': 'Trade union', 'start_paragraph_id': 2, 'start_character': 81, 'end_paragraph_id': 2, 'end_character': 89, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'vacation'}, {'answer': 'health care'}, {'answer': 'retirement'}, {'answer': 'working conditions', 'provenance': [{'wikipedia_id': '17626', 'title': 'Trade union', 'start_paragraph_id': 2, 'start_character': 91, 'end_paragraph_id': 2, 'end_character': 109, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'protecting the integrity of its trade'}]