title: Setting range of a colormap in Matplotlib
body: <p>I'm using matplotlib to plot a simple graph:</p>
  
  <pre><code>cm=plt.get_cmap('Blues')
  
  nx.draw_circular(G,
          node_color='White',
          edge_color=range(G.number_of_edges()),
          edge_cmap=cm,
          node_size=900,
          width=4
          )
  </code></pre>
  
  <p>I want to set a range on the colormap 'Blues' in such a way to delete the white color which is not visible in the draw.</p>
  
  <p>Please help!</p>
  
  <p>Sorry for bad english.</p>