<?xml version="1.0"?>
<xml>
 <pb_type name="parent">
  <input name="i0" />
  <input name="i1" />
  <output name="o" />

  <pb_type name="child">
   <input name="i" />
   <output name="o" />
  </pb_type>

  <interconnect>
   <direct>
    <port type="output" name="o" />
    <port type="input" from="child" name="o" />
   </direct>
   <mux name="mux1">
    <port type="input" name="i0" />
    <port type="input" name="i1" />
    <port type="output" from="child" name="i" />
   </mux>
 </interconnect>
 </pb_type>
</xml>