[James] sat his grandson [Charles] on his knee and asked him what he wanted to be when he grew up. [Charles] said he wanted to be an astronaut. [Charles] and his sister [Martha] went out for coffee. [Martha] asked her brother [Theodore] if he wanted them to bring him anything back, but he said no.
('James', 'Theodore')
[James] sat his grandson [Charles] on his knee and asked him what he wanted to be when he grew up. [Charles] said he wanted to be an astronaut. [Charles] and his sister [Martha] went out for coffee. [Martha] asked her brother [Theodore] if he wanted them to bring him anything back, but he said no.
[{('James', 'grandson', 'Theodore'): [('James', 'grandson', 'Charles'), ('Charles', 'brother', 'Theodore')]}, {('Charles', 'brother', 'Theodore'): [('Charles', 'sister', 'Martha'), ('Martha', 'brother', 'Theodore')]}]
['grandson', 'sister', 'brother']