<leafNode name="source-interface">
  <properties>
    <help>Physical interface used for connection</help>
    <valueHelp>
      <format>interface</format>
      <description>Physical interface used for connection</description>
    </valueHelp>
    <completionHelp>
      <script>${vyos_completion_dir}/list_interfaces.py</script>
    </completionHelp>
  </properties>
</leafNode>