structured typesmutabilityand higher-order functions figure two lists that appear to have the same valuebut don' that univs and univs are bound to different objects can be verified using the built-in python function idwhich returns unique integer identifier for an object this function allows us to test for object equality when we run the code print univs =univs #test value equality print id(univs=id(univs #test object equality print 'id of univs ='id(univsprint 'id of univs ='id(univs it prints true false id of univs id of univs (don' expect to see the same unique identifiers if you run this code the semantics of python says nothing about what identifier is associated with each objectit merely requires that no two objects have the same identifier notice that in figure the elements of univs are not copies of the lists to which techs and ivys are boundbut are rather the lists themselves the elements of univs are lists that contain the same elements as the lists in univsbut they are not the same lists we can see this by running the code print 'ids of univs[ and univs[ ]'id(univs[ ])id(univs[ ]print 'ids of univs [ and univs [ ]'id(univs [ ])id(univs [ ]which prints ids of univs[ and univs[ ids of univs [ and univs [ why does this matterit matters because lists are mutable consider the code techs append('rpi'