diff --git a/src/python/jw/build/lib/SSHClient.py b/src/python/jw/build/lib/SSHClient.py
index 78edd991..c46c2b63 100644
--- a/src/python/jw/build/lib/SSHClient.py
+++ b/src/python/jw/build/lib/SSHClient.py
@@ -73,10 +73,10 @@ class SSHClientCmd(SSHClient): # export
 
     def __del__(self):
         for key, val in self.__askpass_orig.items():
-            if key is None:
+            if val is None:
                 del os.environ[key]
             else:
-                os.setenv(key, val)
+                os.environ[key] = val
         if self.__askpass is not None:
             os.remove(self.__askpass)