title: why networkx.draw() produces nothing?
body: <p>I'm new to python and I'm using IPython, I'm starting to learn about NetworkX, but just in the starting point now I'm noticing that networkx.draw() is not working, here is my code:</p>
  
  <pre><code>    import networkx as nx
      g = nx.Graph()
      g.add_nodes_from([1,2,3,4])
      nx.draw(g)
  </code></pre>
  
  <p>but nothing is drawn!</p>