# Fron https://habr.com/ru/companies/skillfactory/articles/721838/
import os
import networkx as nx
G = nx.Graph()
print(G)
# Graph with 0 nodes and 0 edges
G.add_node("Singapore")
G.add_node("San Francisco")
G.add_node("Tokyo")
print(G)
# Graph with 3 nodes and 0 edges
G.add_nodes_from(["Riga", "Copenhagen"])pip
print(G)
# Graph with 5 nodes and 0 edges
G.add_edge("Singapore","San Francisco")
G.add_edge("San Francisco","Tokyo")
G.add_edges_from(
    [
        ("Riga","Copenhagen"),
        ("Copenhagen","Singapore"),
        ("Singapore","Tokyo"),
        ("Riga","San Francisco"),
        ("San Francisco","Singapore"),
    ]
)
print(G)
# Graph with 5 nodes and 6 edges
nx.draw(G)
os.system("pause")

 G.add_nodes_from(["Riga", "Copenhagen"])pip