如何结合范围和起点

I am new to Go and Hugo site generator and currently creating a simple theme. I am trying to combine a where filter along with first function and I am not able to make it work.

What I want is to get first 10 items in the post section

{{ range where .Data.Pages "Section" "post" }}
    <li><a href="{{.RelPermalink}}">{{.Title}}</a> <em>{{.Summary}}</em></li>
{{ end }}

The above works fine, but how do I make it return only the first 10 items (the below does not work):

{{ range first 10 where .Data.Pages "Section" "post" }}
    <li><a href="{{.RelPermalink}}">{{.Title}}</a> <em>{{.Summary}}</em></li>
{{ end }}

Here's an example from the Hugo Template Functions documentation that I think means you're just missing parentheses:

{{ range first 5 (where .Data.Pages "Section" "post") }}
   {{ .Content }}
{{ end }}