python2.pkgs.ujson: use compatible version

pkgs/development/python-modules/ujson/2.nix

@@ -0,0 +1,28 @@
+{ stdenv
+, buildPythonPackage
+, fetchPypi
+, setuptools_scm
+, pytestCheckHook
+}:
+
+buildPythonPackage rec {
+  pname = "ujson";
+  version = "2.0.3";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "18z9gb9ggy1r464b9q1gqs078mqgrkj6dys5a47529rqk3yfybdx";
+  };
+
+  nativeBuildInputs = [ setuptools_scm ];
+
+  checkInputs = [
+    pytestCheckHook
+  ];
+
+  meta = with stdenv.lib; {
+    homepage = "https://pypi.python.org/pypi/ujson";
+    description = "Ultra fast JSON encoder and decoder for Python";
+    license = licenses.bsd3;
+  };
+}

pkgs/top-level/python-packages.nix

@@ -6993,7 +6993,9 @@ in {
 
   carbon = callPackage ../development/python-modules/carbon { };
 
-  ujson = callPackage ../development/python-modules/ujson { };
+  ujson = if isPy27
+    then callPackage ../development/python-modules/ujson/2.nix { }
+    else callPackage ../development/python-modules/ujson { };
 
   unidecode = callPackage ../development/python-modules/unidecode {};
 
@@ -7853,7 +7855,7 @@ in {
   rxv     = callPackage ../development/python-modules/rxv     { };
 
   userpath = callPackage ../development/python-modules/userpath { };
-  
+
   pooch = callPackage ../development/python-modules/pooch {};
 
 });