如何理解while循环链表

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

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

    def append(self, data):
        new_node = Node(data)
        if not self.head:
            self.head = new_node
            new_node.next = self.head
        else:
            temp = self.head
            while temp.next != self.head:
                temp = temp.next
            temp.next = new_node
            new_node.next = self.head

    def display(self):
        elements = []
        temp = self.head
        while True:
            elements.append(temp.data)
            temp = temp.next
            if temp == self.head:
                break
        return elements

# 示例使用
cll = CircularLinkedList()
cll.append(1)
cll.append(2)
cll.append(3)
print(cll.display())  # 输出: [1, 2, 3]

while temp.next != self.head:
    temp = temp.next

if not self.head:
    print("链表为空")
    return

temp = self.head
prev = None
while temp.next != self.head:
    prev = temp
    temp = temp.next
if prev:
    prev.next = self.head.next
else:
    self.head = self.head.next
del temp