Import transform to Undirected don't merge weight

Way to reproduce:
1) Open the following GraphML file
2) In the import report, select "Undirected"
The n0-n1 edge has a weight = 1. The edge weight has not been merged from n0-n1 and n1-n0

GraphML sample:

<?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="d0" for="edge" attr.name="weight" attr.type="double"/>
  <graph id="G" edgedefault="directed" parse.nodes="5" parse.edges="20" parse.maxindegree="4" parse.maxoutdegree="4">
    <node id="n0"/>
    <edge source="n0" target="n1" label="3.0">
       <data key="d0">3.0</data>
    </edge>
    <edge source="n0" target="n2" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n0" target="n3" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n0" target="n4" label="1">
       <data key="d0">1</data>
    </edge>
    <node id="n1"/>
    <edge source="n1" target="n0" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n1" target="n2" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n1" target="n3" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n1" target="n4" label="1">
       <data key="d0">1</data>
    </edge>
    <node id="n2"/>
    <edge source="n2" target="n0" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n2" target="n1" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n2" target="n3" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n2" target="n4" label="1">
       <data key="d0">1</data>
    </edge>
    <node id="n3"/>
    <edge source="n3" target="n0" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n3" target="n1" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n3" target="n2" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n3" target="n4" label="1">
       <data key="d0">1</data>
    </edge>
    <node id="n4"/>
    <edge source="n4" target="n0" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n4" target="n1" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n4" target="n2" label="1">
       <data key="d0">1</data>
    </edge>
    <edge source="n4" target="n3" label="1">
       <data key="d0">1</data>
    </edge>
  </graph>
</graphml>