diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
index 91923c4..402f678 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -1174,7 +1174,7 @@
 from os.path import join, getsize
 for root, dirs, files in os.walk('python/Lib/email'):
     print root, "consumes",
-    print sum([getsize(join(root, name)) for name in files]),
+    print sum(getsize(join(root, name)) for name in files),
     print "bytes in", len(files), "non-directory files"
     if 'CVS' in dirs:
         dirs.remove('CVS')  # don't visit CVS directories