An IT retailer "Jolly Roger" in Dalby offers products (desktop PCs, tablet PCS and individual components) and services to its customers. They have hired you to develop a class diagram. Customers can place orders. If an order is not paid for immediately, then an invoice is generated. Each order will have a list of product or service offers. Products such as monitors have a current listed price. You will also need to record the purchase price as it might be different to the current listed price. If an order is not paid for immediately, then an invoice should be raised with the due date. Oh - you'll need to record the purchase date too. Services can be repairs, for example, to a PC, or maintenance such as a full system backup. Services should be recorded with a description, the service date and the technician who completed the service. The technician will separately calculate the cost of a repair based on aspects such as component costs, consumerable costs, hour rate and their desire to complete such a repair again. You only need to record the final cost. Maintenance services each have an hourly rate. Jolly Roger recognise both people and organisations as customers. For each organisation, there are some person who are approved to make purchase on behalf of the organisation. Payments are outside the scope for this case study