maps avoid reinventing the wheel using operations provided by an adt to implement other methods of that same adt allows you to take advantage of the abstraction and avoid "reinventing the wheelby duplicating code in several places sure the two sets contain the same number of elementsotherwisethey cannot be equal it would be inefficient to compare the individual elements since we already know the two sets cannot be equal after verifying the size of the listswe can test to see if the self set is subset of setb by calling self issubsetof(setbthis is valid test since two equal sets are subsets of each other and we already know they are of the same size to determine if one set is the subset of anotherwe can iterate over the list of elements in the self set and make sure each is contained in setb if just one element in the self set is not in setbthen it is not subset the implementation of the issubsetof(method is shown in lines - the set union some of the operations create and return new set based on the originalbut the original is not modified this is accomplished by creating new set and populating it with the appropriate data from the other sets consider the union(methodshown in lines - which creates new set from the self set and setb passed as an argument to the method creating new setpopulated with the unique elements of the other two setsrequires three steps( create new set( fill the newset with the elements from setband ( iterate through the elements of the self setduring which each element is added to the newset if that element is not in setb for the first stepwe simply create new instance of the set class the second step is accomplished with the use of the list extend(method it directly copies the entire contents of the list used to store the elements of the self set to the list used to store the elements of the newset for the final stepwe iterate through the elements of setb and add those elements to the the newset that are not in the self set the unique elements are added to the newset by appending them to the list used to store the elements of the newset the remaining operations of the set adt can be implemented in similar fashion and are left as exercises maps searching for data items based on unique key values is very common application in computer science an abstract data type that provides this type of search capability is often referred to as map or dictionary since it maps key to corresponding value consider the problem of university registrar having to manage and process large volumes of data related to students to keep track of the information or records of datathe registrar assigns unique student identification