LeetCode is saying that my answer is , when  is expected.
But a print before return shows that I do return a ListNode, val 1.
Any ideas what is happening here?
code (the method is called by Solution.mergeKLists):
if len(nodelist) == 0: return nodelist first = nodelist if len(nodelist) <= 1: print first print first.val return first for node in nodelist[1:]: first = sort_merge_sorted_ListNodes(first, node) return first ![0_1481436807500_merge_k_sorted_lists.one_case_issue.png](/uploads/files/1481436799997-merge_k_sorted_lists.one_case_issue.png)