You can also ensure `@request_headers` is a non-emptystring array no matter what is passed in like:

```erb
<% if @request_headers and ! @request_headers.empty? -%>

  ## Request rules
<% Array(@request_headers).each do |request_header| -%>
    RequestHeader <%= request_header %>
<% end -%>
<% end -%>
```

Also remember to update the `apache::vhost` template comment with the new fragment and used variables.