diff --git a/pkgs/development/interpreters/python/editable.nix b/pkgs/development/interpreters/python/editable.nix
index df63bbd14fe3..2a492e54c301 100644
--- a/pkgs/development/interpreters/python/editable.nix
+++ b/pkgs/development/interpreters/python/editable.nix
@@ -50,7 +50,7 @@ let
         entry-points
         ;
       dependencies = map lib.getName dependencies';
-      optional-dependencies = lib.mapAttrs (_: lib.getName) optional-dependencies;
+      optional-dependencies = lib.mapAttrs (_: map lib.getName) optional-dependencies;
     };
 
     # Allow empty package