>>> import networkx as nx
>>> from datetime import date
>>> from genealogia import afegir_persona
>>> g = nx.DiGraph()
>>> afegir_persona(g, 'Nadia', date(1910, 5, 10), '', '')
>>> afegir_persona(g, 'Felip', date(1910, 6, 9), '', '')
>>> afegir_persona(g, 'Maria', date(1938, 10, 10), '', '')
>>> afegir_persona(g, 'Robert', date(1936, 2, 20), 'Nadia', 'Felip')
>>> afegir_persona(g, 'Neus', date(1938, 12, 8), 'Nadia', 'Felip')
>>> afegir_persona(g, 'Pau', date(1961, 3, 7), 'Maria', 'Robert')
>>> afegir_persona(g, 'Fina', date(1917, 2, 8), '', '')
>>> afegir_persona(g, 'Elisenda', date(1920, 11, 9), '', '')
>>> afegir_persona(g, 'Gregori', date(1945, 7, 19), 'Fina', 'Felip')
>>> afegir_persona(g, 'Higinio', date(1937, 6, 14), '', '')
>>> afegir_persona(g, 'Remei', date(1941, 2, 8), 'Elisenda', '')
>>> afegir_persona(g, 'Martha', date(1969, 5, 5), '', '')
>>> afegir_persona(g, 'Carlota', date(1974, 1, 9), '', 'Gregori')
>>> afegir_persona(g, 'Oriol', date(1967, 3, 7), 'Remei', 'Higinio')
>>> afegir_persona(g, 'Olga', date(1968, 4, 1), 'Remei', 'Higinio')
>>> afegir_persona(g, 'David', date(1977, 12, 8), 'Remei', 'Higinio')
>>> afegir_persona(g, 'Peter', date(1991, 8, 2), 'Martha', 'Pau')
>>> afegir_persona(g, 'Mireia', date(1995, 2, 3), 'Carlota', 'Oriol')
>>> afegir_persona(g, 'Joan', date(1997, 11, 19), 'Carlota', 'Oriol')
>>> afegir_persona(g, 'Nil', date(2017, 4, 6), 'Mireia', 'Peter')

--ini-enunciat

>>> from genealogia import avis
>>> avis(g, 'Nil')
['Carlota', 'Martha', 'Oriol', 'Pau']
>>> avis(g, 'Mireia')
['Gregori', 'Higinio', 'Remei']
>>> avis(g, 'Remei')
[]

--fi-enunciat

>>> avis(g, 'Carlota')
['Felip', 'Fina']
>>> avis(g, 'Olga')
['Elisenda']