.

wcfs/internal/xbtree.py

@@ -388,7 +388,7 @@ def Restructure(ztree, newStructure):
                     # normal tree node
                     zstate = ()
                     assert len(node.children) == len(node.keyv) + 1
-                    zstate += node.children[0]
+                    zstate += (node.children[0],)
                     for (child, k) in zip(node.children[1:], node.keyv):
                         zstate += (k, child)    # (child0, k0, child1, k1, ..., childN, kN, childN+1)
                     zstate = (zstate,)