Question: what episode of supergirl does she meet the flash
[{'answer': "`` Worlds Finest ''"}, {'provenance': [{'wikipedia_id': '45167756', 'title': 'Supergirl (TV series)', 'start_paragraph_id': 52, 'start_character': 0, 'end_paragraph_id': 52, 'end_character': 850, 'bleu_score': 0.912198388982669, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2021262065725492098}, 'section': 'Section::::Arrowverse.\n'}]}]