DHL has a robust company-wide information system that allows it to have updated information on the processing and current location of each shipped item. Shipped items are the most important part of the DHL product tracking information system. Shipped items are characterized by item number (which is unique), weight, dimensions, insurance amount, destination, and final delivery date. Shipped items are received into the DHL system at a single retail center. Retail centers are characterized by their type, uniqueld, and address. Shipped items reach their destination via one or more standard DHL transportation events (i.e., flights, truck deliveries). The transportation events are characterized by a unique scheduleNumber, a type (e.g, flight, truck), and a deliveryRoute. Please create an Entity Relationship diagram that captures this information about the DHL system