title: draw graph and set edge transparency in networkx
body: <p>I'm tring draw a graph in networkx and at the same time, calculate edge betweenness centrality of every edge, using this to set a different transparency for each edge.
  My code looks like this：</p>
  <pre><code>G = nx.gnp_random_graph(10,0.5) 
  
  options = {
      'node_color':'black',
      'node_size':1,
      'alpha':0.2
  }
  
  edge_betweenness_centrality(G)
  
  nx.draw(G,**options)
  plt.show()
  </code></pre>
  <p>Where the first line is to generate a random graph with 10 nodes, and the <code>edge_betweenness_centrality(G)</code> calculate edge betweenness of every edge.The output just like this:
  <a href="https://i.stack.imgur.com/SjamP.png" rel="nofollow noreferrer">the output of edge_betweenness_centrality(G)</a></p>
  <p>And what I want to do is set the transparency of every edge using the above output. I can only set the unity transparency in options just like the above code <code>'alpha':0.2</code>. So,how do I achieve that?</p>
  <p>Can someone help me? I will be very grateful!</p>