Fixed the class name.
diff --git a/Lib/distutils/command/install_lib.py b/Lib/distutils/command/install_lib.py
index 33cf689..eaaa1c7 100644
--- a/Lib/distutils/command/install_lib.py
+++ b/Lib/distutils/command/install_lib.py
@@ -6,7 +6,7 @@
 from distutils.core import Command
 from distutils.util import copy_tree
 
-class install_py (Command):
+class install_lib (Command):
 
     description = "install pure Python modules"