How does implementation of reverse of doubly linked list work?

Question

How does implementation of reverse of doubly linked list in Python work? Specifically current = current.prev and head=temp.prev

def reverse(head):
    temp = None
    current = head 
        
    
    while current is not None: 
        temp = current.prev  
        current.prev = current.next
        current.next = temp 
        current = current.prev 

    
    if temp is not None: 
        head = temp.prev 
    return head

Answer 1

Take a Doubly linked list: [1] <-> [2] <-> [3]

 head = 1
 temp = None
 current = head = 1

 while current is not None:
     # loop 1, current = 1
     temp = head.prev = None
     current.prev = current.next = 2
     current.next = temp = None
     current = current.next = 2
     # This now looks like this
     # [2] <- [1] -> None 
     # loop 2, current = 2
     temp = current.prev = 1
     current.prev = current.next = 3
     current.next = temp = 1
     current = current.next = 3
     # Now we have
     # [3] <- [2] <-> [1] -> None
     # Last time: 
     temp = current.prev = 2
     current.prev = current.next = None
     current.next = temp = 2
     current = current.next = None
     # [3] <-> [2] <-> [1]
     # break out of loop

          
# I think this should be while temp is not None
if temp is not None:
    temp = 2
    head = temp.prev = 3

return head