Question: when is the 2018 nfl season schedule released
[{'answer': 'April 19 , 2018', 'provenance': [{'wikipedia_id': '48479614', 'title': '2018 NFL season', 'start_paragraph_id': 174, 'start_character': 48, 'end_paragraph_id': 174, 'end_character': 63, 'bleu_score': 1.0, 'section': 'Section::::Regular season.:Saturday flexible scheduling.\n'}]}, {'provenance': [{'wikipedia_id': '48479614', 'title': '2018 NFL season', 'start_paragraph_id': 166, 'start_character': 0, 'end_paragraph_id': 166, 'end_character': 88, 'bleu_score': 0.8172460049207131, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13373660444999642327}, 'section': 'Section::::Regular season.\n'}]}]