Question: who is the song diamonds and rust about
[{'answer': 'Bob Dylan', 'provenance': [{'wikipedia_id': '6628128', 'title': 'Diamonds & Rust (song)', 'start_paragraph_id': 2, 'start_character': 340, 'end_paragraph_id': 2, 'end_character': 349, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6628128', 'title': 'Diamonds & Rust (song)', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 349, 'bleu_score': 0.9694566079002921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10027942723112324059}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6628128', 'title': 'Diamonds & Rust (song)', 'section': 'Section::::Bob Dylan.\n', 'start_paragraph_id': 18, 'end_paragraph_id': 18, 'meta': {'evidence_span': ["You've said when you began writing the song, it started as something else until Dylan", '"Diamonds and Rust" was another magic moment. You\'ve said when you began writing the song, it started as something else until Dylan phoned you. Then it became about him. That must have been one helluva call.']}}]}, {'provenance': [{'wikipedia_id': '6628128', 'title': 'Diamonds & Rust (song)', 'section': 'Section::::Abstract.', 'start_paragraph_id': 2, 'end_paragraph_id': 2, 'meta': {'evidence_span': ['Baez has stated that the lyrics refer to her relationship with Bob Dylan', 'Bob Dylan', 'In the song, Baez recounts an out-of-the-blue phone call from an old lover, which sends her a decade back in time, to a "crummy" hotel in Greenwich Village circa 1964 or 1965; she recalls giving him a pair of cuff-links, and summarizes that memories bring "diamonds and rust". Baez has stated that the lyrics refer to her relationship with Bob Dylan.']}}]}]