title: Graphviz/Python: Recoloring a single node after it has been generated
body: <p>I am getting acquainted with graphviz within Python 2.7.  Is it possible to change the properties of a single node after it has been drawn?</p>
  
  <p>e.g.</p>
  
  <pre><code>from graphviz import Digraph
  q = Digraph()
  q.node('a')
  q.node('b')
  q.edge('a','b')
  
  q
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/IW3fs.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/IW3fs.jpg" alt="Output of simple graph"></a></p>
  
  <p>Is it possible to change the color of node 'b' after the fact?  I am aware that I can set it at the time of generation by</p>
  
  <pre><code>q.node('b', color = 'blue')
  </code></pre>
  
  <p>But, I'd like to be able to change it after generating it.</p>
  
  <p>This link <a href="https://stackoverflow.com/questions/13814640/color-a-particular-node-in-networkx-and-graphviz">Color a particular node in Networkx and Graphviz</a></p>
  
  <p>suggests using the graph's .node property to update a dict</p>
  
  <pre><code>G.node[2]['fillcolor']='red'
  </code></pre>
  
  <p>By analogy, I tried</p>
  
  <pre><code>q.node['b']['color'] = 'blue'
  </code></pre>
  
  <p>which gives an error:</p>
  
  <pre><code>---------------------------------------------------------------------------
  TypeError                                 Traceback (most recent call last)
  &lt;ipython-input-54-43b05071d09a&gt; in &lt;module&gt;()
  ----&gt; 1 q.node['b']['color'] = 'blue'
  
  TypeError: 'instancemethod' object has no attribute '__getitem__'
  </code></pre>
  
  <p>I think this may be because I am not using networkx as in the previous case.</p>
  
  <p>I've also read the graphviz docs at <a href="http://graphviz.org/content/attrs" rel="nofollow noreferrer">http://graphviz.org/content/attrs</a>
  but none of my experiments have worked.  I'm sure it is something straightforward but I am missing it...</p>
  
  <p>--- Old Guy In The Club</p>