from __future__ import annotations from typing import TYPE_CHECKING, List, Tuple, Optional if TYPE_CHECKING: from survey import Answer, Survey, Question

def sort_students(lst: List[Student], attribute: str) -> List[Student]: """ Return a shallow copy of sorted by

=== Precondition === is a attribute name for the Student class

>>> s1 = Student(1, 'Misha') >>> s2 = Student(2, 'Diane') >>> s3 = Student(3, 'Mario') >>> sort_students([s1, s3, s2], 'id') == [s1, s2, s3] True >>> sort_students([s1, s2, s3], 'name') == [s2, s3, s1] True """ return sorted(lst, key=lambda s: getattr(s, attribute))

class Student: """ A Student who can be enrolled in a university course.

=== Public Attributes === id: the id of the student name: the name of the student

=== Representation Invariants === name is not the empty string """

id: int name: str

def __init__(self, id_: int, name: str) -> None: """ Initialize a student with name and id """ # TODO: complete the body of this method

def __str__(self) -> str: """ Return the name of this student """ # TODO: complete the body of this method

def has_answer(self, question: Question) -> bool: """ Return True iff this student has an answer for a question with the same id as and that answer is a valid answer for . """ # TODO: complete the body of this method

def set_answer(self, question: Question, answer: Answer) -> None: """ Record this student's answer to the question . """ # TODO: complete the body of this method

def get_answer(self, question: Question) -> Optional[Answer]: """ Return this student's answer to the question . Return None if this student does not have an answer to """ # TODO: complete the body of this method

class Course: """ A University Course

=== Public Attributes === name: the name of the course students: a list of students enrolled in the course

=== Representation Invariants === - No two students in this course have the same id - name is not the empty string """

name: str students: List[Student]

def __init__(self, name: str) -> None: """ Initialize a course with the name of . """ # TODO: complete the body of this method

def enroll_students(self, students: List[Student]) -> None: """ Enroll all students in in this course.

If adding any student would violate a representation invariant, do not add any of the students in to the course. """ # TODO: complete the body of this method

def all_answered(self, survey: Survey) -> bool: """ Return True iff all the students enrolled in this course have a valid answer for every question in . """ # TODO: complete the body of this method

def get_students(self) -> Tuple[Student, ...]: """ Return a tuple of all students enrolled in this course.

The students in this tuple should be in order according to their id from lowest id to highest id.

Hint: the sort_students function might be useful """ # TODO: complete the body of this method

if __name__ == '__main__': import python_ta python_ta.check_all(config={'extra-imports': ['typing', 'survey']})