diff --git a/Lib/html/__init__.py b/Lib/html/__init__.py
index 335d214..02652ef 100644
--- a/Lib/html/__init__.py
+++ b/Lib/html/__init__.py
@@ -13,7 +13,8 @@
     """
     Replace special characters "&", "<" and ">" to HTML-safe sequences.
     If the optional flag quote is true (the default), the quotation mark
-    character (") is also translated.
+    characters, both double quote (") and single quote (') characters are also
+    translated.
     """
     if quote:
         return s.translate(_escape_map_full)