Cannot read property 'weight' of undefined

[101hanbin]

`import d3py
import networkx as nx

import logging
logging.basicConfig(level=logging.DEBUG)

G=nx.Graph()
G.add_edge(1,2)
G.add_edge(1,3)
G.add_edge(3,2)
G.add_edge(3,4)
G.add_edge(4,2)

use 'with' if you are writing a script and want to serve this up forever

with d3py.NetworkXFigure(G, width=500, height=500) as p:
p += d3py.ForceLayout()
p.show()
`