Question: what are the four stars on the chicago flag
[{'answer': 'symbolize historical events', 'provenance': [{'wikipedia_id': '1213698', 'title': 'Flag of Chicago', 'start_paragraph_id': 2, 'start_character': 345, 'end_paragraph_id': 2, 'end_character': 372, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1213698', 'title': 'Flag of Chicago', 'start_paragraph_id': 2, 'start_character': 157, 'end_paragraph_id': 2, 'end_character': 642, 'bleu_score': 0.7206330688393511, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6932176489461983855}, 'section': 'Section::::Abstract.'}]}]