in uml class diagramswe can show that one class has an attribute whose type is another class using line that connects the two classes the diamond symbol shows that the account class uses the person class in the case of compositionthe diamond symbol is filled (blackplease note that uml class diagrams show the class designi how objects created from this class will look like they show the attributes and methods that will be available for objects created from this class uml diagrams do not show what is going on in python internally (for this we used the diagrams with the grey boxesfor exampleinstance attributes will not be available in the class objectbut we list them in the class diagram class attributes and static methods are underlined in uml class diagrams inheritance makes programmer' life easier inheritance is central principle in oop which leverages commonalities and differences between objects which have to be dealt with in our code the big advantageas we will seeis that inheritance minimizes redundancy (we don' have to write the same code over and over againand thus also facilitates maintenance (if we need to change something in the codewe need to do it only onceif the functionality is shared by different classesthis may sound very abstractso let' have look at concrete example assume our bank offers two different kind of accountssavings accountwe record the account numberholder and balance with each account the balance has to be > we can apply an interest rate which is defined once for all savings accounts money can be deposited into the account the account statement that can be printed includes the account numberholder and balance checking accountwe record the account numberholder and balance with each account the balance has to be greater than or equal to credit range which is determined on per-customer basis for instanceif the credit range determined for anne is $ her balance may not be less than $ money can be deposited into the account the account statement that can be printed includes the account numberholder and balance usuallythe development of an application starts with description of some reallife objects (such as the accountslike above nowwe have to map these descriptions into an object-oriented design we can make the following statements about our application settingannemarie friedrichcis lmu munchenws /