a few more __all__ lists
diff --git a/Lib/popen2.py b/Lib/popen2.py
index e1bf363..954eb29 100644
--- a/Lib/popen2.py
+++ b/Lib/popen2.py
@@ -9,6 +9,8 @@
 import os
 import sys
 
+__all__ = ["popen2", "popen3", "popen4"]
+
 MAXFD = 256     # Max number of file descriptors (os.getdtablesize()???)
 
 _active = []
@@ -155,7 +157,8 @@
         inst = Popen4(cmd, bufsize)
         return inst.fromchild, inst.tochild
 
-
+    __all__.extend(["Popen3", "Popen4"])
+    
 def _test():
     cmd  = "cat"
     teststr = "ab cd\n"