In a sequence diagram, objects and actors are aligned along the top of the diagram. The library users access the catalogue to see whether the item required is available electronically; if it is, the user requests the electronic issue of that item. For copyright reasons, this must be licensed so there is a transaction between the item and the user where the license is agreed. The item to be issued is then sent to a network server object for compression before being sent to the library user. Draw a sequence diagram for the above scenario. Identify the objects; there are three objects: Catalog, Library item and NetServer.