Question: who played gus in the fault in our stars
[{'answer': 'Ansel Elgort', 'provenance': [{'wikipedia_id': '39513921', 'title': 'The Fault in Our Stars (film)', 'start_paragraph_id': 1, 'start_character': 178, 'end_paragraph_id': 1, 'end_character': 190, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '39513921', 'title': 'The Fault in Our Stars (film)', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 49, 'bleu_score': 0.6803749333171201, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9807424560647975727}, 'section': 'Section::::Cast.\n'}]}]