Fix doctest, test

pandas/core/indexes/multi.py

@@ -1649,7 +1649,7 @@ def _set_names(self, names, *, level=None, validate: bool = True) -> None:
         >>> mi
         MultiIndex([(1, 3, 5),
                     (2, 4, 6)],
-                   names=['x', 'y', 'z'])
+                   names=('x', 'y', 'z'))
         >>> mi.names
         ('x', 'y', 'z')
         """,

pandas/core/reshape/pivot.py

@@ -410,7 +410,7 @@ def _all_key(key):
                 if isinstance(piece.index, MultiIndex):
                     # We are adding an empty level
                     transformed_piece.index = MultiIndex.from_tuples(
-                        [all_key], names=piece.index.names + [None]
+                        [all_key], names=piece.index.names + (None,)
                     )
                 else:
                     transformed_piece.index = Index([all_key], name=piece.index.name)

pandas/tests/reshape/merge/test_multi.py

@@ -814,12 +814,10 @@ def test_join_multi_levels2(self):
 
 class TestJoinMultiMulti:
     def test_join_multi_multi(self, left_multi, right_multi, join_type, on_cols_multi):
-        left_names = left_multi.index.names
-        right_names = right_multi.index.names
         if join_type == "right":
-            level_order = right_names + left_names.difference(right_names)
+            level_order = ["Origin", "Destination", "Period", "LinkType", "TripPurp"]
         else:
-            level_order = left_names + right_names.difference(left_names)
+            level_order = ["Origin", "Destination", "Period", "TripPurp", "LinkType"]
         # Multi-index join tests
         expected = (
             merge(