graph = { "a" : ["c"],
          "b" : ["c", "e"],
          "c" : ["a", "b", "d", "e"],
          "d" : ["c"],
          "e" : ["c", "b"],
          "f" : []
}


def genere_arretes(graph):
    edges = []
    for node in graph:
        for neighbour in graph[node]:
            edges.append((node, neighbour))

    return edges

# Affiche les sommets
print(list(graph.keys()))

# Affiche les arrêtes
print(genere_aretes(graph))

# >>> [('a', 'c'), ('c', 'a'), ('c', 'b'), ('c', 'd'), ('c', 'e'), 
#    ('b', 'c'), ('b', 'e'), ('e', 'c'), ('e', 'b'), ('d', 'c')]