title: networkx: nx.draw is not drawing
body: <p>I am running a simple python script on my shell.
  In the script I create a simple graph(2 nodes, 1 edge) and trying to draw it to my screen.</p>
  <p>I do not get any error, but the graph is not showing</p>
  <pre><code>import matplotlib
  import networkx as nx
  
  G = nx.DiGraph()
  G.add_node(1)
  G.add_node(2)
  G.add_edge(1, 2)
  nx.draw(G)
  </code></pre>
  <p>I don't get any error but there is no output.</p>
  <p>Can you help?</p>