The next step is to initialize the libraries we have just included in the project. The persistence library includes an inventory library (Waher.Runtime.Inventory) that helps with dynamic type-related tasks, as well as keeping track of available types, interfaces and which ones have implemented which interfaces in the runtime environment. This functionality is used by the object database defined in the persistence libraries. The object database figures out how to store, load, search for, and create objects, using only their class definitions appended with a minimum of metadata in the form of attributes. So, one of the first things we need to do during startup is to tell the inventory environment which assemblies it and, by extension, the persistence library can use. We do this as follows:

Log.Informational("Starting application."); 
Types.Initialize( 
   typeof(FilesProvider).GetTypeInfo().Assembly, 
   typeof(App).GetTypeInfo().Assembly); 

Here, Types is a static class defined in the Waher.Runtime.Inventory namespace. We initialize it by providing an array of assemblies it can use. In our case, we include the assembly of the persistence library, as well as the assembly of our own application.