diff --git a/pkgs/development/python-modules/pytest-factoryboy/default.nix b/pkgs/development/python-modules/pytest-factoryboy/default.nix
index b5e65085abec..48c5020a44f8 100644
--- a/pkgs/development/python-modules/pytest-factoryboy/default.nix
+++ b/pkgs/development/python-modules/pytest-factoryboy/default.nix
@@ -21,6 +21,9 @@ buildPythonPackage rec {
     sha256 = "0m1snyybq2k51khlydhisq300vzys897vdbsicph628iran950hn";
   };
 
+  # TODO: remove in next release, it's removed in master.
+  postPatch = "substituteInPlace tox.ini --replace '--pep8' ''";
+
   propagatedBuildInputs = [ factory_boy inflection pytest ];
 
   # The project uses tox, which we can't. So we simply run pytest manually.