Question: when was the last time liverpool played champions league
[{'answer': '2017', 'provenance': [{'wikipedia_id': '9650877', 'title': 'Liverpool F.C. in European football', 'start_paragraph_id': 45, 'start_character': 1353, 'end_paragraph_id': 45, 'end_character': 1357, 'bleu_score': 1.0, 'section': 'Section::::History.:Decline and Resurgence (2010–present).\n'}]}]