diff -r be3b41703822 Lib/tokenize.py
--- a/Lib/tokenize.py	Tue Mar 10 16:32:50 2015 +0100
+++ b/Lib/tokenize.py	Tue Mar 10 10:09:58 2015 -0700
@@ -24,6 +24,7 @@
 __credits__ = ('GvR, ESR, Tim Peters, Thomas Wouters, Fred Drake, '
                'Skip Montanaro, Raymond Hettinger, Trent Nelson, '
                'Michael Foord')
+import builtins
 from codecs import lookup, BOM_UTF8
 import collections
 from io import TextIOWrapper
@@ -428,8 +429,9 @@
 
     return default, [first, second]
 
-
-_builtin_open = open
+# Store this in the module to make it more reliably available at interpreter
+# shutdown (issue 22599)
+_builtin_open = builtins.open
 
 def open(filename):
     """Open a file in read only mode using the encoding detected by