$6\mathrm{.}11$ LAB: Course gradebook with dict

Step $1$: Inspect the Gradebook abstract base class

The read$-$only Gradebook.py file has a declaration for the Gradebook abstract base class. Access Gradebook.py by clicking on the orange arrow next to main.py at the top of the coding window.

The Gradebook class stores a collection of entries for a course. Conceptually, a gradebook entry is a $($assignment name, student ID$,$ score$)$ triplet. Each assignment name is a string, each student ID is an integer, and each score is a float. A score is entered into the gradebook via the set$\_$score$()$ method.

The Gradebook class has six abstract methods that must be implemented in an inheriting class.

Step $2$: Add attributes to CourseGradebook class

The CourseGradebook class inherits from Gradebook and is declared in CourseGradebook.py$.$ Inspect each method that must be implemented. Choose one or more attributes to store gradebook data and add the attributes to the CourseGradebook class. Several options exist, so grading does not analyze the choice of attributes.

Step $3$: Implement CourseGradebook's set$\_$score$()$ and get$\_$score$()$ methods

Implement the set$\_$score$()$ method to enter a single entry into the gradebook. set$\_$score$()$ has parameters for the assignment name, student ID$,$ and score. How the entry is stored depends on the attributes chosen in step $2.$

Implement the get$\_$score$()$ method to get a single score from the gradebook. get$\_$score$()$ has parameters for the assignment name and student ID$,$ and returns a float for the corresponding score. None is returned if no such entry exists in the gradebook.

Code in main.py calls test$\_$get$\_$score$\_$and$\_$set$\_$score$()$ to test both methods. Run your program in develop mode and ensure that the test passes before proceeding further.

Step $4$: Implement the remaining CourseGradebook methods

Implement the remaining methods according to the specifications below.

get$\_$assignment$\_$scores$()$ takes a string for the assignment name and returns a dict that maps a student ID to the student's corresponding score for the assignment. An entry exists in the returned dict only if a score has been entered with the set$\_$score$()$ method. An empty dict is returned if no such assignment exists in the grade book.

get$\_$sorted$\_$assignment$\_$names$()$ returns a list with all distinct assignment names, sorted in ascending order.

get$\_$sorted$\_$student$\_$iDs$()$ returns a list with all distinct student IDs, sorted in ascending order.

get$\_$student$\_$scores$()$ gets all scores that exist in the gradebook for the student whose ID equals the method parameter. Scores are returned as a dict that maps an assignment name to the student's corresponding score for that assignment.