1 files changed, 1 insertions, 3 deletions
diff --git a/sphinx/util/jsonimpl.py b/sphinx/util/jsonimpl.py
index eb4117f90..8054be0d7 100644
--- a/sphinx/util/jsonimpl.py
+++ b/sphinx/util/jsonimpl.py
@@ -11,8 +11,6 @@
 import json
 from collections import UserString
 
-from six import text_type
-
 if False:
     # For type annotation
     from typing import Any, IO  # NOQA
@@ -23,7 +21,7 @@ class SphinxJSONEncoder(json.JSONEncoder):
     def default(self, obj):
         # type: (Any) -> str
         if isinstance(obj, UserString):
-            return text_type(obj)
+            return str(obj)
         return super().default(obj)