Question: who played gandalf in lord of the rings trilogy
[{'answer': 'Sir Ian Murray McKellen', 'provenance': [{'wikipedia_id': '15308', 'title': 'Ian McKellen', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 23, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '15308', 'title': 'Ian McKellen', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 297, 'bleu_score': 0.6085186913586831, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2808844403452313701}, 'section': 'Section::::Abstract.'}]}]