def main():
"""main function"""
node1 = GraphNode(name="1", value=1)
node2 = GraphNode(name="2", value=2)
node3 = GraphNode(name="3", value=3)
node4 = GraphNode(name="4", value=4)
node1.add_children([(node3, 3), (node4, 10)])
node3.add_children([(node2, 1), (node1, 2)])
node4.add_children([(node2, 4)])
node5 = GraphNode(name="5", value=5, children=[(node1, 10)])
graph = Graph([node1, node2, node3, node4])
graph.add_node(node5)
print(shortest_path(graph, node1, node2, 0, []))
