2. (a) In the context of Object Oriented (OO) analysis, when modelling associations between classes, a designer would not model them as bidirectional unless there was an evident need to do so. Explain, in terms of the implementation of the model, why bidirectional associations would be avoided. In your answer, provide an example class diagram and code that illustrates your explanation. [15 Marks] (b) (i) The Law of Demeter is also known as the Principle of Least Knowledge. Give a brief summary of this principle. [3 Marks] (ii) Give a brief description of three of the four guides within the Law of Demeter and provide both a class diagram and a sequence diagram that illustrates the structure and behaviour of each one. [15 Marks]