Question: what did uk soccer officials use before whistles
[{'answer': 'a white handkerchief', 'provenance': [{'wikipedia_id': '501260', 'title': 'Referee (association football)', 'start_paragraph_id': 15, 'start_character': 85, 'end_paragraph_id': 15, 'end_character': 105, 'bleu_score': 1.0, 'section': 'Section::::Uniform and equipment.:Whistle.\n'}]}, {'provenance': [{'wikipedia_id': '501260', 'title': 'Referee (association football)', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 843, 'bleu_score': 0.9683237089750321, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11851469666731288256}, 'section': 'Section::::Uniform and equipment.:Whistle.\n'}]}]