Question: who is the musical superstar that helped justin bieber get started
[{'answer': 'Usher', 'provenance': [{'wikipedia_id': '23680998', 'title': 'Justin Bieber', 'start_paragraph_id': 10, 'start_character': 694, 'end_paragraph_id': 10, 'end_character': 699, 'bleu_score': 1.0, 'section': 'Section::::Career.:2008–2009: Career beginnings and "My World".\n'}]}, {'provenance': [{'wikipedia_id': '23680998', 'title': 'Justin Bieber', 'start_paragraph_id': 11, 'start_character': 0, 'end_paragraph_id': 11, 'end_character': 752, 'bleu_score': 0.965400604802336, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15881816890779174441}, 'section': 'Section::::Career.:2008–2009: Career beginnings and "My World".\n'}]}]