求链表最大绝对值的Pythonic方法

class Node:
    def __init__(self, value):
        self.value = value
        self.next = None

class LinkedList:
    def __init__(self):
        self.head = None

    def add_node(self, value):
        new_node = Node(value)
        if self.head is None:
            self.head = new_node
        else:
            current = self.head
            while current.next:
                current = current.next
            current.next = new_node

    def find_max_absolute(self):
        if self.head is None:
            return None
        max_value = abs(self.head.value)
        current = self.head.next
        while current:
            max_value = max(max_value, abs(current.value))
            current = current.next
        return max_value

# 创建链表并添加节点
linked_list = LinkedList()
linked_list.add_node(-2)
linked_list.add_node(5)
linked_list.add_node(3)
linked_list.add_node(-9)

# 求最大绝对值
max_absolute = linked_list.find_max_absolute()
print("最大绝对值为:", max_absolute)