分别设计班级类、教室类、教师类，通过课程类把它们关联起来

班级类：

class Class:
    def __init__(self, class_id, class_name, students):
        self.class_id = class_id
        self.class_name = class_name
        self.students = students

教室类：

class Classroom:
    def __init__(self, classroom_id, capacity):
        self.classroom_id = classroom_id
        self.capacity = capacity

教师类：

class Teacher:
    def __init__(self, teacher_id, teacher_name):
        self.teacher_id = teacher_id
        self.teacher_name = teacher_name

课程类：

from datetime import datetime

class Course:
    def __init__(self, course_id, course_name, teacher, classroom, class_obj, start_time, end_time):
        self.course_id = course_id
        self.course_name = course_name
        self.teacher = teacher
        self.classroom = classroom
        self.class_obj = class_obj
        self.start_time = start_time
        self.end_time = end_time

以上四个类都是独立的类，通过课程类实现关联。

班级类和课程类关联：

class_obj = Class(class_id=1, class_name='Class A', students=[])
course_obj = Course(course_id=1, course_name='Math', teacher=teacher_obj, classroom=classroom_obj, class_obj=class_obj, start_time=datetime(2022, 9, 1, 8, 0), end_time=datetime(2022, 9, 1, 10, 0))
class_obj.courses.append(course_obj)

教室类和课程类关联：

classroom_obj = Classroom(classroom_id=1, capacity=50)
course_obj = Course(course_id=1, course_name='Math', teacher=teacher_obj, classroom=classroom_obj, class_obj=class_obj, start_time=datetime(2022, 9, 1, 8, 0), end_time=datetime(2022, 9, 1, 10, 0))
classroom_obj.courses.append(course_obj)

教师类和课程类关联：

teacher_obj = Teacher(teacher_id=1, teacher_name='John')
course_obj = Course(course_id=1, course_name='Math', teacher=teacher_obj, classroom=classroom_obj, class_obj=class_obj, start_time=datetime(2022, 9, 1, 8, 0), end_time=datetime(2022, 9, 1, 10, 0))
teacher_obj.courses.append(course_obj)