Issue #11159: SAX parser now supports unicode file names.
diff --git a/Lib/xml/sax/expatreader.py b/Lib/xml/sax/expatreader.py
index 92a79c1..9de3e72 100644
--- a/Lib/xml/sax/expatreader.py
+++ b/Lib/xml/sax/expatreader.py
@@ -108,7 +108,10 @@
 
     def prepareParser(self, source):
         if source.getSystemId() is not None:
-            self._parser.SetBase(source.getSystemId())
+            base = source.getSystemId()
+            if isinstance(base, unicode):
+                base = base.encode('utf-8')
+            self._parser.SetBase(base)
 
     # Redefined setContentHandler to allow changing handlers during parsing