1 files changed, 4 insertions, 0 deletions
diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index 771d4ce5818..5a7d2cac127 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -1834,3 +1834,7 @@ class StringIO(TextIOWrapper):
         # TextIOWrapper tells the encoding in its repr. In StringIO,
         # that's a implementation detail.
         return object.__repr__(self)
+
+    @property
+    def encoding(self):
+        return None