python.pkgs.nbformat: move expression

pkgs/development/python-modules/nbformat/default.nix

···
+{ lib
+, buildPythonPackage
+, fetchPypi
+, pytest
+, glibcLocales
+, ipython_genutils
+, traitlets
+, testpath
+, jsonschema
+, jupyter_core
+}:
+
+buildPythonPackage rec {
+  pname = "nbformat";
+  version = "4.3.0";
+  name = "${pname}-${version}";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "5febcce872672f1c97569e89323992bdcb8573fdad703f835e6521253191478b";
+  };
+  LC_ALL="en_US.UTF-8";
+
+  checkInputs = [ pytest glibcLocales ];
+  propagatedBuildInputs = [ ipython_genutils traitlets testpath jsonschema jupyter_core ];
+
+  # Failing tests and permission issues
+  doCheck = false;
+
+  meta = {
+    description = "The Jupyter Notebook format";
+    homepage = "http://jupyter.org/";
+    license = lib.licenses.bsd3;
+    maintainers = with lib.maintainers; [ fridh ];
+  };
+}

pkgs/top-level/python-packages.nix

···
     };
   };
 
-  nbformat = buildPythonPackage rec {
-    version = "4.3.0";
-    name = "nbformat-${version}";
-
-    src = pkgs.fetchurl {
-      url = "mirror://pypi/n/nbformat/${name}.tar.gz";
-      sha256 = "5febcce872672f1c97569e89323992bdcb8573fdad703f835e6521253191478b";
-    };
-    LC_ALL="en_US.UTF-8";
-    buildInputs = with self; [ pytest pkgs.glibcLocales ];
-    propagatedBuildInputs = with self; [ipython_genutils traitlets testpath jsonschema jupyter_core];
-
-    # Failing tests and permission issues
-    doCheck = false;
-
-    meta = {
-      description = "The Jupyter Notebook format";
-      homepage = "http://jupyter.org/";
-      license = licenses.bsd3;
-      maintainers = with maintainers; [ fridh ];
-    };
-  };
+  nbformat = callPackage ../development/python-modules/nbformat { };
 
   nbxmpp = buildPythonPackage rec {
     name = "nbxmpp-${version}";