python.pkgs.args: move to separate expression

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

@@ -0,0 +1,17 @@
+{ stdenv, buildPythonPackage, fetchPypi }:
+
+buildPythonPackage rec {
+  pname = "args";
+  version = "0.1.0";
+  name = "${pname}-${version}";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "a785b8d837625e9b61c39108532d95b85274acd679693b71ebb5156848fcf814";
+  };
+
+  meta = with stdenv.lib; {
+    description = "Command Arguments for Humans";
+    homepage = "https://github.com/kennethreitz/args";
+  };
+}

pkgs/top-level/python-packages.nix

@@ -613,19 +613,7 @@ in {
 
   APScheduler = callPackage ../development/python-modules/APScheduler { };
 
-  args = buildPythonPackage rec {
+  args = callPackage ../development/python-modules/args { };
-    name = "args-0.1.0";
-
-    src = pkgs.fetchurl {
-      url = "mirror://pypi/a/args/${name}.tar.gz";
-      sha256 = "a785b8d837625e9b61c39108532d95b85274acd679693b71ebb5156848fcf814";
-    };
-
-    meta = {
-      description = "Command Arguments for Humans";
-      homepage = "https://github.com/kennethreitz/args";
-    };
-  };
 
   argcomplete = callPackage ../development/python-modules/argcomplete { };