Question: who sings if this world were mine with luther
[{'answer': 'Cheryl Lynn', 'provenance': [{'wikipedia_id': '1683816', 'title': 'If This World Were Mine', 'start_paragraph_id': 3, 'start_character': 31, 'end_paragraph_id': 3, 'end_character': 42, 'bleu_score': 1.0, 'section': 'Section::::Cover versions.\n'}]}, {'provenance': [{'wikipedia_id': '1683816', 'title': 'If This World Were Mine', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 230, 'bleu_score': 0.887508747915121, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7136605949595406288}, 'section': 'Section::::Cover versions.:Luther Vandross and Cheryl Lynn version.\n'}]}]