pythonPackages.convertdate: add python2-compatible expression

pkgs/development/python-modules/convertdate/2.2.x.nix

@@ -0,0 +1,36 @@
+{ lib
+, buildPythonPackage
+, fetchFromGitHub
+, pymeeus
+, pytz
+, pytestCheckHook
+}:
+
+buildPythonPackage rec {
+  pname = "convertdate";
+  version = "2.2.2";
+
+  # Tests are not available in the PyPI tarball so use GitHub instead.
+  src = fetchFromGitHub {
+    owner = "fitnr";
+    repo = pname;
+    rev = "v${version}";
+    sha256 = "1xgi7x9b9kxm0q51bqnmwdm5lp8vwhx5yk4d1b23r37spz9dbhw5";
+  };
+
+  propagatedBuildInputs = [
+    pymeeus
+    pytz
+  ];
+
+  checkInputs = [
+    pytestCheckHook
+  ];
+
+  meta = with lib; {
+    homepage = "https://github.com/fitnr/convertdate";
+    description = "Utils for converting between date formats and calculating holidays";
+    license = licenses.mit;
+    maintainers = with maintainers; [ jluttine ];
+  };
+}

pkgs/top-level/python-packages.nix

@@ -1472,7 +1472,10 @@ in {
 
   contextvars = callPackage ../development/python-modules/contextvars { };
 
-  convertdate = callPackage ../development/python-modules/convertdate { };
+  convertdate = if isPy27 then
+    callPackage ../development/python-modules/convertdate/2.2.x.nix { }
+  else
+    callPackage ../development/python-modules/convertdate { };
 
   cookiecutter = callPackage ../development/python-modules/cookiecutter { };