networkx中边缘的颜色栏

我想在networkx图中获取边缘的颜色条.这是一段代码片段

import networkx as nx
import matplotlib.colors as colors
import matplotlib.cm as cmx

n = 12 # Number of clusters
w = 21 # Number of weeks

m = Basemap(
    projection='merc',
    ellps = 'WGS84',
    llcrnrlon=-98.5,
    llcrnrlat=25,
    urcrnrlon=-60,
    urcrnrlat=50,
    lat_ts=0,
    resolution='i',
    suppress_ticks=True)

mx, my = m(list(ccentroids['lon']), list(ccentroids['lat']))

# The NetworkX part
# put map projection coordinates in pos dictionary
G = nx.DiGraph()
G.add_nodes_from(range(n))
for i in range(n):
    for j in range(n):
       if P_opt[i,j] > 0.5 and i != j:
           G.add_edge(i,j, weight = P_opt[i,j])

pos = {i : (mx[i], my[i]) for i in range(n)}

# Add a color_map for the edges
jet = cm = plt.get_cmap('jet')
cNorm  = colors.Normalize(vmin=0, vmax=np.max(P_opt))
scalarMap = cmx.ScalarMappable(norm=cNorm, cmap=jet)
colorList = []
weights_list = []

for i in G.edges():
   a, b = i
   colorVal = scalarMap.to_rgba(G.edge[a][b]['weight'])
   colorList.append(colorVal)
   weights_list.append(G.edge[a][b]['weight'])

plt.clf()
fig = plt.figure()
ax = fig.add_subplot(111, axisbg='w', frame_on=False)
fig.set_size_inches(18.5, 10.5)

# draw the network
nodes = nx.draw_networkx_nodes(G, pos, node_size=100, node_color=q[:,t], cmap =     plt.cm.jet, 
                               font_size=8, with_labels=False, label='Cluster centroids')
edges = nx.draw_networkx_edges(G, pos, edge_color=colorList)

m.drawcountries()    
m.bluemarble()

这给了我以下图像:

现在我想为边缘添加一个颜色条.我尝试过像这样的事情,

plt.sci(edges)
edges.set_array(np.array(weights_list))
plt.colorbar(shrink = 0.8)

这给了我一个像这样的图像:

箭头和边缘的颜色似乎不同.我怎么能纠正这个？谢谢.

编辑:我试图通过修改边缘线使用以下代码:

edges = nx.draw_networkx_edges(G, pos, edge_color=colorList, edge_cmap = plt.cm.jet)
plt.colorbar(edges)

这给了我一个错误 TypeError: You must first set_array for mappable

将edge_color更改为weights_list我得到以下图片: