#1651995: fix _convert_ref for non-ASCII characters.
diff --git a/Lib/sgmllib.py b/Lib/sgmllib.py
index e5fbd32..104b25f 100644
--- a/Lib/sgmllib.py
+++ b/Lib/sgmllib.py
@@ -396,7 +396,7 @@
             n = int(name)
         except ValueError:
             return
-        if not 0 <= n <= 255:
+        if not 0 <= n <= 127:
             return
         return self.convert_codepoint(n)