gpodder: lift listparser out of gnome-feeds

it's being removed in https://github.com/NixOS/nixpkgs/pull/320801 i.e. when i next update nixpkgs

pkgs/additional/gpodder-configured/default.nix

@@ -10,9 +10,7 @@ let
   remove-extra = static-nix-shell.mkPython3Bin {
     pname = "gpodder-remove-extra";
     srcRoot = ./.;
-    pyPkgs = _ps: {
+    pyPkgs = [ "listparser" ];
-      "gnome-feeds.listparser" = gnome-feeds.listparser;
-    };
     pkgs = {
       # important for this to explicitly use `gpodder` here, because it may be overriden/different from the toplevel `gpodder`!
       inherit gpodder;

pkgs/additional/gpodder-configured/gpodder-remove-extra

@@ -1,5 +1,5 @@
 #!/usr/bin/env nix-shell
-#!nix-shell -i python3 -p "python3.withPackages (ps: [ gnome-feeds.listparser ])" -p gpodder
+#!nix-shell -i python3 -p "python3.withPackages (ps: [ ps.listparser ])" -p gpodder
 
 from dataclasses import dataclass, field
 import listparser

pkgs/python-packages/default.nix

@@ -3,6 +3,7 @@
   depthcharge-tools = callPackage ./depthcharge-tools { };
   feedsearch-crawler = callPackage ./feedsearch-crawler { };
   fastcluster = callPackage ./fastcluster { };
+  listparser = callPackage ./listparser { };
   ols = callPackage ./ols { };
   pa-dlna = callPackage ./pa-dlna { };
   pyln-bolt7 = callPackage ./pyln-bolt7 { };

pkgs/python-packages/listparser/default.nix

@@ -0,0 +1,39 @@
+{
+  buildPythonPackage,
+  fetchPypi,
+  lib,
+  python3,
+  requests,
+  six,
+}:
+
+buildPythonPackage rec {
+  pname = "listparser";
+  version = "0.18";
+
+  src = fetchPypi {
+    pname = "listparser";
+    inherit version;
+    sha256 = "0hdqs1mmayw1r8yla43hgb4d9y3zqs5483vgf8j9ygczkd2wrq2b";
+  };
+
+  propagatedBuildInputs = [
+    requests
+    six
+  ];
+
+  checkPhase = ''
+    runHook preCheck
+    ${python3.interpreter} lptest.py
+    runHook postCheck
+  '';
+
+  meta = with lib; {
+    description = "Parser for subscription lists";
+    homepage = "https://github.com/kurtmckee/listparser";
+    license = licenses.lgpl3Plus;
+    maintainers = [ maintainers.colinsane ];
+    platforms = platforms.linux;
+  };
+}
+