{{ template "sectionsnav" . }}
{{ define "sectionsnav" }}
{{ $sec := where .Sections ".Params.unlisted" "!=" "true" }}
{{ if gt (len $sec) 0 }}
<ul>
{{ range $sec }}
<li>
    <a href="{{ .Permalink }}">{{ .Title }}</a>
    {{ template "sectionsnav" .  }}
</li>
{{ end }}
</ul>
{{ end }}
{{ end }}