diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b2be92b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+result
diff --git a/overlay.nix b/overlay.nix
index ad3667e..73e64a2 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -1,4 +1,15 @@
-final: prev: {
+final: prev:
+let
+  inherit (prev.lib)
+    mapAttrs'
+    removeSuffix
+    ;
+in
+mapAttrs' (name: _: {
+  value = final.callPackage ./pkgs/${name} { };
+  name = removeSuffix ".nix" name;
+}) (builtins.readDir ./pkgs)
+// {
   formats = prev.formats // {
     xml = import ./xml.nix { pkgs = final; };
   };
diff --git a/python_overlay.nix b/python_overlay.nix
index 3dc4b4f..79af2dd 100644
--- a/python_overlay.nix
+++ b/python_overlay.nix
@@ -1,6 +1,11 @@
 final: prev:
-with prev.lib;
+let
+  inherit (prev.lib)
+    mapAttrs'
+    removeSuffix
+    ;
+in
 mapAttrs' (name: _: {
-  value = final.callPackage (./python-pkgs/${name}) { };
+  value = final.callPackage ./python-pkgs/${name} { };
   name = removeSuffix ".nix" name;
 }) (builtins.readDir ./python-pkgs)