用Python分别设计班级类、教师类、教室类，通过课程类把它们关联起来。各类的属性、方法自己确定。

下面是一个简单的代码示例：

class Student:
    def __init__(self, name, id):
        self.name = name
        self.id = id
        self.courses = []
    
    def add_course(self, course):
        self.courses.append(course)
    
    def remove_course(self, course):
        self.courses.remove(course)


class Teacher:
    def __init__(self, name, id):
        self.name = name
        self.id = id
        self.courses = []
    
    def add_course(self, course):
        self.courses.append(course)
    
    def remove_course(self, course):
        self.courses.remove(course)


class Classroom:
    def __init__(self, room_number):
        self.room_number = room_number
        self.capacity = 30
        self.schedule = {}
    
    def reserve(self, date, time, course):
        if len(self.schedule) >= self.capacity:
            return False
        if date not in self.schedule:
            self.schedule[date] = {}
        if time in self.schedule[date]:
            return False
        self.schedule[date][time] = course
        return True


class Course:
    def __init__(self, name, teacher, classroom, date, time):
        self.name = name
        self.teacher = teacher
        self.classroom = classroom
        self.date = date
        self.time = time
        self.students = []
        self.teacher.add_course(self)
        self.classroom.reserve(date, time, self)
    
    def add_student(self, student):
        self.students.append(student)
        student.add_course(self)
    
    def remove_student(self, student):
        self.students.remove(student)
        student.remove_course(self)

上述代码定义了四个类：学生类、教师类、教室类和课程类。其中，学生和教师类都有一个属性 courses，表示该学生或教师所选修或教授的课程列表。教室类有一个 schedule 属性，表示该教室的使用安排；课程类则包含了教师、教室、学生等多个对象的引用，并且在创建课程对象时会自动加入相应的教师和教室的课程列表中，同时也会将课程添加到学生的课程列表中。