03. SoftUni Students

def softuni_students(*args, **kwargs):
    result = []
    invalid_courses = []
    for course_id, username in sorted(args, key=lambda item: item[1]):
        if course_id in kwargs:
            course = kwargs[course_id]
            result.append(f"*** A student with the username {username} has successfully finished the course {course}!")
        else:
            invalid_courses.append(username)
    if invalid_courses:
        result.append(f"!!! Invalid course students: {', '.join(sorted(invalid_courses))}")
    return "\n".join(result)