I am not sure why I get this error- "'Umbraco.Web.PublishedContentModels.ProductDocuments' does not contain a definition for 'GetPropertyValue'". I have used the same set up for other nested content on this page and it worked. If you have any insights on what might be wrong I would appreciate it.

@inherits Umbraco.Web.Mvc.UmbracoTemplatePage
@{
    Layout = "Master.cshtml";
    var node = Model.Content;
    var home = node.Site();
    var productML = home.Descendant("markets");
    var product = @CurrentPage.Parent().Descendants("product").First();
}


    @foreach(var stuff in product.Children.Where("Visible")){
            if (stuff.HasValue("relatedDocuments"))
                {
                    foreach (var item in stuff.GetPropertyValue<IEnumerable<IPublishedContent>>("relatedDocuments"))
                    {
                        if (item.HasValue("documentFile") && item.HasValue("documentName"))
                        {
                                var file = item.GetPropertyValue<IPublishedContent>("documentFile");
                                <div class="boxspacenope">
                                <div class="outline3">
                                    <div class="row">
                                        <div class="col s6 m6 l6" align="left">
                                            <div class="title3"><b>@item.GetPropertyValue("documentName")</b></div>
                                        </div>
                                        <div class="col s3 m3 l3" align="center">
                                        </div>
                                        <div class="col s3 m3 l3" align="center">
                                            <ul class="links">
                                                <li>
                                                    <a href="@file.Url" target="_blank"><div class="underline">Download</div></a>
                                                </li>
                                            </ul>
                                        </div>
                                    </div>
                                </div>
                            </div>
                        }
                    }
                }
    }