python.pkgs.decorator: move expression

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

@@ -0,0 +1,20 @@
+{ lib
+, buildPythonPackage
+, fetchPypi
+}:
+
+buildPythonPackage rec {
+  pname = "decorator";
+  version = "4.0.11";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "953d6bf082b100f43229cf547f4f97f97e970f5ad645ee7601d55ff87afdfe76";
+  };
+
+  meta = {
+    homepage = https://pypi.python.org/pypi/decorator;
+    description = "Better living through Python with decorators";
+    license = lib.licenses.mit;
+  };
+}

pkgs/top-level/python-packages.nix

@@ -4101,21 +4101,7 @@ in {
     };
   };
 
-  decorator = buildPythonPackage rec {
+  decorator = callPackage ../development/python-modules/decorator { };
-    name = "decorator-${version}";
-    version = "4.0.11";
-
-    src = pkgs.fetchurl {
-      url = "mirror://pypi/d/decorator/${name}.tar.gz";
-      sha256 = "953d6bf082b100f43229cf547f4f97f97e970f5ad645ee7601d55ff87afdfe76";
-    };
-
-    meta = {
-      homepage = https://pypi.python.org/pypi/decorator;
-      description = "Better living through Python with decorators";
-      license = licenses.mit;
-    };
-  };
 
   deform = buildPythonPackage rec {
     name = "deform-2.0a2";