python.pkgs.webassets: move to a separate file

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

@@ -0,0 +1,25 @@
+{ lib, buildPythonPackage, fetchurl, pyyaml, nose, jinja2, mock, pytest }:
+
+buildPythonPackage rec {
+  name = "webassets-${version}";
+  version = "0.12.1";
+
+  src = fetchurl {
+    url = "mirror://pypi/w/webassets/${name}.tar.gz";
+    sha256 = "1nrqkpb7z46h2b77xafxihqv3322cwqv6293ngaky4j3ff4cing7";
+  };
+
+  propagatedBuildInputs = [ pyyaml ];
+  checkInputs = [ nose jinja2 mock pytest ];
+
+  # Needs Babel CLI tool
+  doCheck = false;
+  checkPhase = "py.test";
+
+  meta = with lib; {
+    description = "Media asset management for Python, with glue code for various web frameworks";
+    homepage = http://github.com/miracle2k/webassets/;
+    license = licenses.bsd2;
+    maintainers = with maintainers; [ abbradar ];
+  };
+}

pkgs/top-level/python-packages.nix

@@ -17735,32 +17735,7 @@ EOF
 
   waitress-django = callPackage ../development/python-modules/waitress-django { };
 
-  webassets = buildPythonPackage rec {
+  webassets = callPackage ../development/python-modules/webassets { };
-    name = "webassets-${version}";
-    version = "0.12.1";
-
-    src = pkgs.fetchurl {
-      url = "mirror://pypi/w/webassets/${name}.tar.gz";
-      sha256 = "1nrqkpb7z46h2b77xafxihqv3322cwqv6293ngaky4j3ff4cing7";
-    };
-
-    buildInputs = with self; [ nose jinja2 mock pytest ];
-    propagatedBuildInputs = with self; [ pyyaml ];
-
-    doCheck = false;
-
-    checkPhase = ''
-      py.test
-    '';
-
-    meta = {
-      description = "Media asset management for Python, with glue code for various web frameworks";
-      homepage = "http://github.com/miracle2k/webassets/";
-      license = licenses.bsd2;
-      platforms = platforms.all;
-      maintainers = with maintainers; [ abbradar ];
-    };
-  };
 
   webcolors = callPackage ../development/python-modules/webcolors { };