I'm guessing this is something super simple, but I've hit a dead end.

I am trying to render a MultiNode Treepicker2 datatype in a partial to reuse on multiple pages throughout my site.

If I have the properties in a in single document type, and only use it on that template, this works as expected:

    @inherits Umbraco.Web.Mvc.UmbracoTemplatePage
    @using Umbraco.Web.Models;

    @{
        var typedMultiNodeTreePicker = Model.Content.GetPropertyValue<IEnumerable<IPublishedContent>>("tenYearsArticle");
        foreach (var item in typedMultiNodeTreePicker)
        {
            <p class="sidebar-ten-years-entry-title"><a href="@item.Url">@item.Name</a></p>
        }
     }

but if I try to move those properties in a stand-alone content type to reuse in a partial across the site, this doesn't work:

@inherits Umbraco.Web.Mvc.UmbracoTemplatePage
@inherits Umbraco.Web.Mvc.UmbracoViewPage<IPublishedContent>
@using Umbraco.Web
@using Umbraco.Web.Models;

@{
    var tenyears = Umbraco.TypedContent(1687).Children("tenYearsAgoThisWeek");
    var typedMultiNodeTreePicker = tenyears.GetPropertyValue<IEnumerable<IPublishedContent>>("tenYearsArticle");
    foreach (var item in typedMultiNodeTreePicker)
    {

    }
 }

this gives the error: System.Collections.Generic.IEnumerable<Umbraco.Core.Models.IPublishedContent>' does not contain a definition for 'GetPropertyValue' and the best extension method overload 'Umbraco.Web.PublishedContentExtensions.GetPropertyValue<T>(Umbraco.Core.Models.IPublishedContent, string)' has some invalid arguments

It seems like it should work, I'm misunderstanding something fundamental about how IPublishedContent works. Thank you