while not queue.is_empty():
r = queue.dequeue()
for node in r.links:
if node.visited is False:
print(node, target)
if node == target:
return True
node.visited = True
queue.enqueue(node)
return False
if __name__ == '__main__':
g = DirectedGraph()
a = g.add_node('A')
b = g.add_node('B')
c = g.add_node('C')
d = g.add_node('D')
e = g.add_node('E')
f = g.add_node('F')
a.points_to(b)
a.points_to(f)
b.points_to(d)
b.points_to(e)
c.points_to(b)
d.points_to(c)
