Question: The professional boxer, who held the WBO ligh-middleweight from 2015-2016, has a younger brother who is also a professional boxer; what is this brother's name?
{'answer': 'Callum Smith', 'supporting_facts': [['Liam Smith (boxer)', 0], ['Liam Smith (boxer)', 1], ['Callum Smith', 0], ['Callum Smith', 1]]}