<?xml version="1.0" encoding="UTF-8"?>
<graphml xmlns="http://graphml.graphdrawing.org/xmlns"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns
    http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">

  <key id="d1" for="edge" attr.name="weight" attr.type="double">
    <default>1.0</default>
  </key>

  <graph id="G" edgedefault="directed">
    <edge source="1" target="2"/>
    <edge source="2" target="3">
      <data key="d1">2.0</data>
    </edge>
    <edge source="3" target="1"/>

    <node id="1"/>
    <node id="2"/>
    <node id="3"/>
  </graph>
</graphml>
