[Python] Head seems to be acting strangely if its value is observed [closed]

I'm solving Leetcode problem 19.

# head is a singly-linked list
temp = head
temp = temp.next
print("Node: " + str(temp))


This outputs the contents of a linked list. It looks something like Node: ListNode{val: 3, next: ListNode{...}}.

However, if I add the line print(temp.val) to the end of the code, I get an AttributeError: 'NoneType' object has no attribute 'val'.

Even more strangely, stdout now shows the single line "Node: None".

It seems like temp becomes None if its value is going to be observed in the future. I can't think of any explanation for this behavior.

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