Question: when was the 24 second shot clock introduced
[{'answer': 'the 1954 -- 55 season'}, {'provenance': [{'wikipedia_id': '1002256', 'title': 'Shot clock', 'start_paragraph_id': 15, 'start_character': 303, 'end_paragraph_id': 15, 'end_character': 946, 'bleu_score': 0.6550786313687661, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14797873522245429453}, 'section': 'Section::::History.:Creation.\n'}]}]