Question: when does trials of apollo 4 come out
[{'answer': 'Fall 2019'}, {'provenance': [{'wikipedia_id': '50985871', 'title': 'The Trials of Apollo', 'start_paragraph_id': 16, 'start_character': 0, 'end_paragraph_id': 16, 'end_character': 78, 'bleu_score': 0.600498175219752, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7120693854425811522}, 'section': 'Section::::Books.:"The Tyrant\'s Tomb".\n'}]}]