diff --git a/pkgs/development/python-modules/pypass/default.nix b/pkgs/development/python-modules/pypass/default.nix
index ee73ddc09ec4..ad8e17fc8bee 100644
--- a/pkgs/development/python-modules/pypass/default.nix
+++ b/pkgs/development/python-modules/pypass/default.nix
@@ -42,9 +42,9 @@ buildPythonPackage rec {
   ];
 
   # Remove enum34 requirement if Python >= 3.4
-  postPatch = lib.optionalString (pythonAtLeast "3.4") ''
-    substituteInPlace requirements.txt --replace "enum34" ""
-  '';
+  pythonRemoveDeps = lib.optionals (pythonAtLeast "3.4") [
+    "enum34"
+  ];
 
   build-system = [ setuptools ];