#1535: rename __builtin__ module to builtins.
diff --git a/Lib/sunau.py b/Lib/sunau.py
index f255502..b312501 100644
--- a/Lib/sunau.py
+++ b/Lib/sunau.py
@@ -153,8 +153,8 @@
 
     def __init__(self, f):
         if type(f) == type(''):
-            import __builtin__
-            f = __builtin__.open(f, 'rb')
+            import builtins
+            f = builtins.open(f, 'rb')
         self.initfp(f)
 
     def __del__(self):
@@ -282,8 +282,8 @@
 
     def __init__(self, f):
         if type(f) == type(''):
-            import __builtin__
-            f = __builtin__.open(f, 'wb')
+            import builtins
+            f = builtins.open(f, 'wb')
         self.initfp(f)
 
     def __del__(self):