你可以在Course类中添加一个方法来检查它是否与另一个Course冲突。当你添加一个课程时，让它循环遍历现有的课程，看看它是否与你的Schedule中的现有课程冲突。

class Course:
    def __init__(self, name, classroom, instructor, day, start_time, end_time):
        self.name = name
        self.classroom = classroom
        self.instructor = instructor
        self.day = day
        self.start_time = start_time
        self.end_time = end_time

    def check_collision(self, other):
        if self.day == other.day:
            if other.start_time < self.start_time < other.end_time:
                return True
            if other.start_time < self.end_time < other.end_time:
                return True
            if self.start_time < other.start_time < self.end_time:
                return True
            if self.start_time < other.end_time < self.end_time:
                return True
        return False

class Schedule:
    def __init__(self):
        self.courses = []
        self.program = [
            ["9","10","11","12","13","14","15","16","17"],
            ["9","10","11","12","13","14","15","16","17"],
            ["9","10","11","12","13","14","15","16","17"],
            ["9","10","11","12","13","14","15","16","17"],
            ["9","10","11","12","13","14","15","16","17"],
        ]

    def add_course(self, course):
        for c in self.courses:
            if course.check_collision(c):
                print(f'New course has collision with course: {c.name} on {c.day}: {c.start_time}-{c.end_time}')
                break
        else:
            self.courses.append(course)

    def print_schedule(self):
        days = ["Monday","Tuesday","Wednesday","Thursday","Friday"]
        program = [x.copy() for x in self.program]
        for course in self.courses:
            for j in range(course.start_time-9,course.end_time-8):
                program[days.index(course.day)][j] += f"      {course.name} class from {course.instructor} at {course.classroom}"
        for i in range(len(days)):
            print(days[i],":")
            for k in program[i]:
                print(k)

根据你的代码，你可以为类Schedule定义一个比较函数，你可以创建一个Schedule对象来保存很多课程，所以如果你想访问Schedule中的一门课程，你需要执行schedule.courses[i]，但是我建议你在课程类中添加下面的函数来解决你的问题。

def compare_course(self, other_course):
my_time = {i for i in range(start_time, end_time+1)}
other_time = {i for i in range(other_course.start_time, other_course.end_time+1)}
if my_time.intersection(other_course.time) != set():
    return "Course Collides"
else:
    return "Course does not collide"