Question: who claimed to have discovered an iron law of oligarchy
[{'answer': 'Robert Michels', 'provenance': [{'wikipedia_id': '449071', 'title': 'Iron law of oligarchy', 'start_paragraph_id': 1, 'start_character': 91, 'end_paragraph_id': 1, 'end_character': 105, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '449071', 'title': 'Iron law of oligarchy', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 326, 'bleu_score': 0.913499617140693, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11245902900873141315}, 'section': 'Section::::Abstract.'}]}]