Templates are no different then any other ASP.NET page. They require references and imports of any needed assemblies, too.
Since we're using the DatabaseSchema object (remember our previous property), we need to add a reference to the SchemaExplorer assembly, like so:
<%@ Assembly Name="SchemaExplorer" %>
And, finally, we'll be referencing the instance of DatabaseSchema throughout our template, so we'll need to import the SchemaExplorer namespace so that we have context to the object:
<%@ Import Namespace="SchemaExplorer" %>