Question: what is the story the song of roland about
[{'answer': 'Battle of Roncevaux Pass', 'provenance': [{'wikipedia_id': '226080', 'title': 'The Song of Roland', 'start_paragraph_id': 1, 'start_character': 70, 'end_paragraph_id': 1, 'end_character': 94, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '226080', 'title': 'The Song of Roland', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 321, 'bleu_score': 0.871467614909702, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14226338231855197732}, 'section': 'Section::::Abstract.'}]}]