from networkx import DiGraph
from vrpy import VehicleRoutingProblem

# Define the network
G = DiGraph()
G.add_edge("Source",1,cost=1,time=2)
G.add_edge("Source",2,cost=2,time=1)
G.add_edge(1,"Sink",cost=0,time=2)
G.add_edge(2,"Sink",cost=2,time=3)
G.add_edge(1,2,cost=1,time=1)
G.add_edge(2,1,cost=1,time=1)

# Define the customers demands
G.nodes[1]["demand"] = 5
G.nodes[2]["demand"] = 4

# Define the Vehicle Routing Problem
prob = VehicleRoutingProblem(G, load_capacity=10, duration=5)

# Solve and display solution value
prob.solve()
print(prob.best_value)
3
print(prob.best_routes)
{1: ["Source",2,1,"Sink"]}