Python导入类在另一个类中用作嵌套/内部类

Python版本:

Python 3.6

我有这门课:

class Backup:
    class Create:
        @staticmethod
        def all():
            print('create all')

        @staticmethod
        def user(username):
            print('create user: ' + username)

        @staticmethod
        def file(filename):
            print('create file: ' + filename)

    class Restore:
        @staticmethod
        def all():
            print('restore all')

        @staticmethod
        def user(username):
            print('restore user: ' + username)

        @staticmethod
        def file(filename):
            print('restore file: ' + filename)

    class Delete:
        @staticmethod
        def all():
            print('delete all')

        @staticmethod
        def user(username):
            print('delete user: ' + username)

        @staticmethod
        def file(filename):
            print('delete file: ' + filename)

但我想将嵌套类移动到它们自己的模块中并导入它们,但我不知道如何做到这一点。这是我基于一些类似堆栈溢出问题的最新尝试。很明显,它不起作用:

from Models.Create import Create

class Backup(Create):

是否有人知道如何实现我的目标,这样我仍然可以调用类中的方法,如下所示: Backup.Create.all()