>>> import networkx as nx

>>> lrius = [ ['Jari', 'Amazones'], ['Xingú', 'Amazones'], ['Iriri', 'Xingú'],
...  ['Paru', 'Amazones'], ['Tapajós', 'Amazones'], ['Teles Pires', 'Tapajós'],
...  ['Juruena', 'Tapajós'], ['Arinos', 'Juruena'], 
...  ['Guaviare', 'Orinoco'], ['Inírida', 'Guaviare'], ['Arauca', 'Orinoco'] ]
>>> gr = nx.DiGraph()
>>> gr.add_edges_from(lrius)

>>> from rius import recorregut

--ini-enunciat

>>> recorregut(gr, 'Arinos')
['Arinos', 'Juruena', 'Tapajós', 'Amazones']
>>> recorregut(gr, 'Paru')
['Paru', 'Amazones']
>>> recorregut(gr, 'Orinoco')
['Orinoco']

--fi-enunciat

>>> recorregut(gr, 'Inírida')
['Inírida', 'Guaviare', 'Orinoco']