'Gets a course progress status.
Args:
request (Request): Django request object.
course_id (string): URI element specifying the course location.
Return:
A JSON serialized representation of the requesting user\'s current grade status.'

def get(self, request, course_id):

    course = self._get_course(course_id, request.user, 'load')
    if isinstance(course, Response):
        return course
    grade_user = self._get_effective_user(request, course)
    if isinstance(grade_user, Response):
        return grade_user
    prep_course_for_grading(course, request)
    course_grade = CourseGradeFactory().create(grade_user, course)
    return Response([{'username': grade_user.username, 'course_key': course_id, 'passed': course_grade.passed, 'percent': course_grade.percent, 'letter_grade': course_grade.letter_grade}])
