函数中动态构造对象的窄返回类型

from abc import ABC, abstractmethod

# 定义一个权限接口
class Permission(ABC):
    @abstractmethod
    def check(self, user):
        pass

# 普通用户权限类
class UserPermission(Permission):
    def check(self, user):
        print(f"Checking permissions for {user} as a regular user.")

# 管理员权限类
class AdminPermission(Permission):
    def check(self, user):
        print(f"Checking permissions for {user} as an admin.")

# 动态构造权限对象的工厂函数
def get_permission(role):
    if role == "admin":
        return AdminPermission()
    else:
        return UserPermission()

# 客户端代码
def main():
    user_role = "admin"  # 可以根据实际情况动态获取
    permission = get_permission(user_role)
    permission.check("Alice")

if __name__ == "__main__":
    main()