在不破坏现有约定的情况下向导出的类型添加函数

// 原始类型定义
export interface Person {
  name: string;
  age: number;
}

// 扩展类型
export interface Person {
  greet(): string;
}

// 实现扩展方法
Person.prototype.greet = function() {
  return `Hello, my name is ${this.name} and I am ${this.age} years old.`;
};

# 原始类定义
class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

# 扩展类
class GreetMixin:
    def greet(self):
        return f"Hello, my name is {self.name} and I am {self.age} years old."

# 组合使用
class PersonWithGreet(Person, GreetMixin):
    pass

# 使用
person = PersonWithGreet("Alice", 30)
print(person.greet())  # 输出: Hello, my name is Alice and I am 30 years old.