Question: where is the tigris and euphrates river valley located
[{'answer': 'Western Asia', 'provenance': [{'wikipedia_id': '209798', 'title': 'Tigris–Euphrates river system', 'start_paragraph_id': 1, 'start_character': 79, 'end_paragraph_id': 1, 'end_character': 91, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '209798', 'title': 'Tigris–Euphrates river system', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 351, 'bleu_score': 0.87540210596635, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13661181486030889835}, 'section': 'Section::::Abstract.'}]}]