story: [Christopher] met with his mother, [Gabrielle] and his son [Alfred], for afternoon tea.
query: ('Gabrielle', 'Alfred')
clean_story: [Christopher] met with his mother, [Gabrielle] and his son [Alfred], for afternoon tea.
proof_state: [{('Gabrielle', 'grandson', 'Alfred'): [('Gabrielle', 'son', 'Christopher'), ('Christopher', 'son', 'Alfred')]}]