Question: where does the expression charlie horse come from
[{'answer': 'Canada and the United States', 'provenance': [{'wikipedia_id': '1060399', 'title': 'Charley horse', 'start_paragraph_id': 1, 'start_character': 65, 'end_paragraph_id': 1, 'end_character': 93, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1060399', 'title': 'Charley horse', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 978, 'bleu_score': 0.7911417063675781, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2753505861065773101}, 'section': 'Section::::Abstract.'}]}]