如何在python中向已有的导入添加新方法？特别是电影

class Movie:
    def __init__(self, title, director):
        self.title = title
        self.director = director

    def play(self):
        print("Playing movie:", self.title)


# 扩展Movie类，添加新的方法
class ExtendedMovie(Movie):
    def __init__(self, title, director, duration):
        super().__init__(title, director)
        self.duration = duration

    def play_trailer(self):
        print("Playing trailer for:", self.title)

    def play(self):
        super().play()
        print("Duration:", self.duration)


# 使用扩展后的类
movie = ExtendedMovie("The Avengers", "Joss Whedon", 143)
movie.play()  # 调用扩展的方法
movie.play_trailer()  # 调用新添加的方法

# movie.py
class Movie:
    def __init__(self, title, director):
        self.title = title
        self.director = director

    def play(self):
        print("Playing movie:", self.title)


def play_trailer(movie):
    print("Playing trailer for:", movie.title)


# main.py
from movie import Movie, play_trailer

movie = Movie("The Avengers", "Joss Whedon")
movie.play()

play_trailer(movie)  # 调用新添加的函数