title: Graph-Tool -> Networkx
body: <p>I am trying to save a graph generated by Graph-Tool and read it in with Networkx. I tried the GraphML format. Unfortunately I encounter </p>
  
  <pre><code>KeyError: 'vector_float'
  </code></pre>
  
  <p>as in the GraphML file a property is saved as the following:</p>
  
  <pre><code>&lt;key id="key1" for="node" attr.name="plot_color" attr.type="vector_float" /&gt;
  </code></pre>
  
  <p>I have read that the problem regarding the conversion Graph-Tool &lt;---> Networkx exists for a while now. Is there any solution to this?</p>