Question: who sings lead vocals on have a cigar
[{'answer': 'Roy Harper', 'provenance': [{'wikipedia_id': '1428751', 'title': 'Have a Cigar', 'start_paragraph_id': 2, 'start_character': 20, 'end_paragraph_id': 2, 'end_character': 30, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1428751', 'title': 'Have a Cigar', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 243, 'bleu_score': 0.955027111100031, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14498995149742765741}, 'section': 'Section::::Abstract.'}]}]