python2.pkgs.jupyter_client: pin at 5.x

Version 6.x dropped python2 compatibility.

pkgs/development/python-modules/jupyter_client/5.nix

@@ -0,0 +1,39 @@
+{ lib
+, buildPythonPackage
+, fetchPypi
+, traitlets
+, jupyter_core
+, pyzmq
+, dateutil
+, isPyPy
+, py
+, tornado
+}:
+
+buildPythonPackage rec {
+  pname = "jupyter_client";
+  version = "5.3.4";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "60e6faec1031d63df57f1cc671ed673dced0ed420f4377ea33db37b1c188b910";
+  };
+
+  propagatedBuildInputs = [
+    traitlets
+    jupyter_core
+    pyzmq
+    dateutil
+    tornado
+  ] ++ lib.optional isPyPy py;
+
+  # Circular dependency with ipykernel
+  doCheck = false;
+
+  meta = {
+    description = "Jupyter protocol implementation and client libraries";
+    homepage = "https://jupyter.org/";
+    license = lib.licenses.bsd3;
+    maintainers = with lib.maintainers; [ fridh ];
+  };
+}

pkgs/top-level/python-packages.nix

@@ -4180,7 +4180,10 @@ in {
     inherit (pkgs.jsonnet) name src;
   };
 
-  jupyter_client = callPackage ../development/python-modules/jupyter_client { };
+  jupyter_client = if isPy3k then
+    callPackage ../development/python-modules/jupyter_client { }
+  else
+    callPackage ../development/python-modules/jupyter_client/5.nix { };
 
   jupyter_core = callPackage ../development/python-modules/jupyter_core { };