rotate list

def rotateRight(self,head,k):
        first,second,preserve_first,preserve_second,i = head,head,head,head,0
        while second != None and i < k:
            second = second.next
            i += 1
            if i < k and second == None: #when k bigger than the length of the list, we get the remaining of k%i and recompute second pointer initial position again !
                k = k % i
                i = 0
                second = head
        if second == None or k == 0: #if second reach None which means k is equal to the length of list,then nothing change; so does when k is zero
            return head
        while second != None:
            preserve_first,preserve_second = first,second
            first,second = first.next,second.next
        preserve_second.next = head
        head = first
        preserve_first.next = None
        return head