LC559 Insert into a Cyclic Sorted List

class Solution:
    """
    @param: node: a list node in the list
    @param: x: An integer
    @return: the inserted new list node
    """
    def insert(self, node, x):
        #case1 node = None
        #case 2.a node.val bigger than max => find max and find min  
        #case 2.b node.val between min and max (assuming there is min and max =>  at least 2 nodes =>
        if not node:
            node = ListNode(x)
            node.next = node
            return node
        max = node # find max in linkedlist
        head = node
        while (head != max.next and max.next.val >= max.val):
                max = max.next  # update max
            # to prevent deadloop, set up head and check with node.next
        min = max.next
        # case 2.a  insertion
        if x >= max.val or x <= min.val:
            newNode = ListNode(x,min)
            max.next = newNode
        else:
            cur = min
            while cur.next.val < x :
                cur = cur.next
            newNode = ListNode(x,cur.next)
            cur.next = newNode
        return newNode