diff --git a/pkgs/development/interpreters/python/python-packages-base.nix b/pkgs/development/interpreters/python/python-packages-base.nix
index e3a92bef52f3..22c829bf736c 100644
--- a/pkgs/development/interpreters/python/python-packages-base.nix
+++ b/pkgs/development/interpreters/python/python-packages-base.nix
@@ -19,22 +19,13 @@ let
     lib.mirrorFunctionArgs f (
       origArgs:
       let
-        args = lib.fix (
-          lib.extends (_: previousAttrs: {
-            passthru = (previousAttrs.passthru or { }) // {
-              overridePythonAttrs = newArgs: makeOverridablePythonPackage f (overrideWith newArgs);
-            };
-          }) (_: origArgs)
-        );
-        result = f args;
-        overrideWith = newArgs: args // (if pkgs.lib.isFunction newArgs then newArgs args else newArgs);
+        result = f origArgs;
+        overrideWith = newArgs: origArgs // lib.toFunction newArgs origArgs;
       in
-      if builtins.isAttrs result then
+      if lib.isAttrs result then
         result
-      else if builtins.isFunction result then
-        {
+        // {
           overridePythonAttrs = newArgs: makeOverridablePythonPackage f (overrideWith newArgs);
-          __functor = self: result;
         }
       else
         result