Revert copy_reg -> copyreg rename.
diff --git a/Misc/cheatsheet b/Misc/cheatsheet
index 1ce1996..e699359 100644
--- a/Misc/cheatsheet
+++ b/Misc/cheatsheet
@@ -1864,7 +1864,7 @@
 compileall       Force "compilation" of all .py files in a directory.
 configparser     Configuration file parser (much like windows .ini files)
 copy             Generic shallow and deep copying operations.
-copyreg          Helper to provide extensibility for pickle/cPickle.
+copy_reg         Helper to provide extensibility for pickle/cPickle.
 csv              Read and write files with comma separated values.
 dbhash           (g)dbm-compatible interface to bsdhash.hashopen.
 dircache         Sorted list of files in a dir, using a cache.