diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 429c16d2cdb..971585d9bd4 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -24840,7 +24840,7 @@ in {
 
     postPatch = ''
       # argparse is needed for python < 2.7, which we do not support anymore.
-      substituteInPlace setup.py --replace "argparse"
+      substituteInPlace setup.py --replace "argparse" ""
 
       # # fixes a transient error when collecting tests, see https://bugs.launchpad.net/python-neutronclient/+bug/1508547
       sed -i '510i\        return None, False' unittest2/loader.py