[Robert] and [Marie] have a daughter named [Michelle], and [Marie] has a son named [Allan]. [Ronald] bought a book for his father [Robert].
('Allan', 'Ronald')
[Robert] and [Marie] have a daughter named [Michelle], and [Marie] has a son named [Allan]. [Ronald] bought a book for his father [Robert].
[{('Allan', 'brother', 'Ronald'): [('Allan', 'father', 'Robert'), ('Robert', 'son', 'Ronald')]}, {('Allan', 'father', 'Robert'): [('Allan', 'sister', 'Michelle'), ('Michelle', 'father', 'Robert')]}, {('Allan', 'sister', 'Michelle'): [('Allan', 'mother', 'Marie'), ('Marie', 'daughter', 'Michelle')]}]
['mother', 'daughter', 'father', 'son']