diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index d88af031135..09f93953a8c 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -13472,13 +13472,22 @@ in modules // {
 
 
   mccabe = buildPythonPackage (rec {
-    name = "mccabe-0.5.2";
+    name = "mccabe-0.4.0";
 
     src = pkgs.fetchurl {
       url = "mirror://pypi/m/mccabe/${name}.tar.gz";
-      sha256 = "1zss8c5cn8wvxsbjzv70dxymybh3cjzrjl19vxfbnyvmidng0wrl";
+      sha256 = "0yr08a36h8lqlif10l4xcikbbig7q8f41gqywir7rrvnv3mi4aws";
     };
 
+    # See https://github.com/flintwork/mccabe/issues/31
+    postPatch = ''
+      cp "${pkgs.fetchurl {
+        url = "https://raw.githubusercontent.com/flintwork/mccabe/"
+            + "e8aea16d28e92bd3c62601275762fc9c16808f6c/test_mccabe.py";
+        sha256 = "0xhjxpnaxvbpi4myj9byrban7a5nrw931br9sgvfk42ayg4sn6lm";
+      }}" test_mccabe.py
+    '';
+
     buildInputs = with self; [ pytestrunner pytest ];
 
     meta = {