Question: What outspoken abolitionist and author of "An Appeal to the Coloured Citizens of the World" was also the father of one of the first black men to pass the Massachusetts bar?
{'answer': 'David Walker', 'supporting_facts': [['Edward G. Walker', 0], ['Edward G. Walker', 2], ['David Walker (abolitionist)', 0], ['David Walker (abolitionist)', 2]]}