1 files changed, 3 insertions, 6 deletions
diff --git a/sphinx/versioning.py b/sphinx/versioning.py
index 409dc5e3a..2c6569932 100644
--- a/sphinx/versioning.py
+++ b/sphinx/versioning.py
@@ -11,13 +11,11 @@
 """
 import pickle
 import warnings
-from itertools import product
+from itertools import product, zip_longest
 from operator import itemgetter
 from os import path
 from uuid import uuid4
 
-from six.moves import zip_longest
-
 from sphinx.deprecation import RemovedInSphinx30Warning
 from sphinx.transforms import SphinxTransform
 
@@ -25,7 +23,6 @@ if False:
     # For type annotation
     from typing import Any, Iterator  # NOQA
     from docutils import nodes  # NOQA
-    from sphinx.util.typing import unicode  # NOQA
 
 try:
     import Levenshtein
@@ -122,7 +119,7 @@ def merge_doctrees(old, new, condition):
 
 
 def get_ratio(old, new):
-    # type: (unicode, unicode) -> float
+    # type: (str, str) -> float
     """Return a "similiarity ratio" (in percent) representing the similarity
     between the two strings where 0 is equal and anything above less than equal.
     """
@@ -136,7 +133,7 @@ def get_ratio(old, new):
 
 
 def levenshtein_distance(a, b):
-    # type: (unicode, unicode) -> int
+    # type: (str, str) -> int
     """Return the Levenshtein edit distance between two strings *a* and *b*."""
     if a == b:
         return 0