diff --git a/ssl/ssl.py b/ssl/ssl.py
index 09639b4a..e3273cdb 100644
--- a/ssl/ssl.py
+++ b/ssl/ssl.py
@@ -1 +1,6 @@
 from ussl import *
+
+# Constants
+for sym in "CERT_NONE", "CERT_OPTIONAL", "CERT_REQUIRED":
+    if sym not in globals():
+        globals()[sym] = object()