Question: who established brotherhood between the muhajireen and ansar
[{'answer': 'Muhammad', 'provenance': [{'wikipedia_id': '8902524', 'title': 'Brotherhood among the Sahabah', 'start_paragraph_id': 1, 'start_character': 93, 'end_paragraph_id': 1, 'end_character': 101, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '8902524', 'title': 'Brotherhood among the Sahabah', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 222, 'bleu_score': 0.9419661180380051, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16159431909449678901}, 'section': 'Section::::Abstract.'}]}]