Python中如何实现访问者模式？

from abc import ABC, abstractmethod

# 定义抽象的访问者接口
class Visitor(ABC):
    @abstractmethod
    def visit_concrete_element_a(self, element):
        pass

    @abstractmethod
    def visit_concrete_element_b(self, element):
        pass

# 具体的访问者类
class ConcreteVisitor1(Visitor):
    def visit_concrete_element_a(self, element):
        print(f"ConcreteVisitor1 visiting {element.__class__.__name__}")

    def visit_concrete_element_b(self, element):
        print(f"ConcreteVisitor1 visiting {element.__class__.__name__}")

class ConcreteVisitor2(Visitor):
    def visit_concrete_element_a(self, element):
        print(f"ConcreteVisitor2 visiting {element.__class__.__name__}")

    def visit_concrete_element_b(self, element):
        print(f"ConcreteVisitor2 visiting {element.__class__.__name__}")

# 定义抽象的元素接口
class Element(ABC):
    @abstractmethod
    def accept(self, visitor):
        pass

# 具体的元素类
class ConcreteElementA(Element):
    def accept(self, visitor):
        visitor.visit_concrete_element_a(self)

class ConcreteElementB(Element):
    def accept(self, visitor):
        visitor.visit_concrete_element_b(self)

# 对象结构
class ObjectStructure:
    def __init__(self):
        self.elements = []

    def attach(self, element):
        self.elements.append(element)

    def detach(self, element):
        self.elements.remove(element)

    def accept(self, visitor):
        for element in self.elements:
            element.accept(visitor)

# 使用示例
if __name__ == "__main__":
    structure = ObjectStructure()
    structure.attach(ConcreteElementA())
    structure.attach(ConcreteElementB())

    visitor1 = ConcreteVisitor1()
    visitor2 = ConcreteVisitor2()

    structure.accept(visitor1)
    structure.accept(visitor2)