Changed items to use BTree_keys.

src/BTrees/TreeSetTemplate.c

@@ -114,7 +114,7 @@ static struct PyMethodDef TreeSet_methods[] = {
      "has_key(key) -- Test whether the bucket contains the given key"},
   {"keys",	(PyCFunction) BTree_keys,	METH_VARARGS,
      "keys() -- Return the keys"},
-  {"items",	(PyCFunction) BTree_items,	METH_VARARGS,
+  {"items",	(PyCFunction) BTree_keys,	METH_VARARGS,
      "items() -- Return the items"},
   {"maxKey", (PyCFunction) BTree_maxKey,	METH_VARARGS,
    "maxKey([key]) -- Fine the maximum key\n\n"