pythonPackages.locket: Move to own file

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

···
+{ stdenv, buildPythonPackage, fetchPypi, pytest }:
+
+buildPythonPackage rec {
+  pname = "locket";
+  version = "0.2.0";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "1d4z2zngrpqkrfhnd4yhysh66kjn4mblys2l06sh5dix2p0n7vhz";
+  };
+
+  buildInputs = [ pytest ];
+
+  # weird test requirements (spur.local>=0.3.7,<0.4)
+  doCheck = false;
+
+  meta = with stdenv.lib; {
+    description = "Locket implements a lock that can be used by multiple processes provided they use the same path.";
+    homepage = https://github.com/mwilliamson/locket.py;
+    license = licenses.bsd2;
+    maintainers = with maintainers; [ teh ];
+  };
+}

pkgs/top-level/python-packages.nix

···
 
   linuxfd = callPackage ../development/python-modules/linuxfd { };
 
-  locket = buildPythonPackage rec {
-    name = "locket-${version}";
-    version = "0.2.0";
-
-    src = pkgs.fetchurl {
-      url = "mirror://pypi/l/locket/${name}.tar.gz";
-      sha256 = "1d4z2zngrpqkrfhnd4yhysh66kjn4mblys2l06sh5dix2p0n7vhz";
-    };
-
-    buildInputs = with self; [ pytest ];
-    propagatedBuildInputs = with self; [  ];
-
-    # weird test requirements (spur.local>=0.3.7,<0.4)
-    doCheck = false;
-
-    meta = {
-      description = "Locket implements a lock that can be used by multiple processes provided they use the same path.";
-      homepage = "https://github.com/mwilliamson/locket.py";
-      license = licenses.bsd2;
-      maintainers = with maintainers; [ teh ];
-    };
-  };
+  locket = callPackage ../development/python-modules/locket { };
 
   tblib = buildPythonPackage rec {
     name = "tblib-${version}";