pyditz: make python.pkgs.cerberus11 private to it.

pkgs/applications/misc/pyditz/cerberus.nix

@@ -0,0 +1,19 @@
+{ stdenv, buildPythonPackage, fetchPypi, pytestrunner, pytest }:
+
+buildPythonPackage rec {
+  pname = "Cerberus";
+  version = "1.1";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "1pxzr8sfm2hc5s96m9k044i44nwkva70n0ypr6a35v73zn891cx5";
+  };
+
+  checkInputs = [ pytestrunner pytest ];
+
+  meta = with stdenv.lib; {
+    homepage = http://python-cerberus.org/;
+    description = "Lightweight, extensible schema and data validation tool for Python dictionaries";
+    license = licenses.mit;
+  };
+}

pkgs/applications/misc/pyditz/default.nix

@@ -1,18 +1,22 @@
 { stdenv, pythonPackages }:
 
-pythonPackages.buildPythonApplication rec {
+with pythonPackages;
+
+let
+  cerberus_1_1 = callPackage ./cerberus.nix { };
+in buildPythonApplication rec {
   pname = "pyditz";
   version = "0.10.3";
 
-  src = pythonPackages.fetchPypi {
+  src = fetchPypi {
     inherit pname version;
     sha256 = "0hxxz7kxv9gsrr86ccsc31g7bc2agw1ihbxhd659c2m6nrqq5qaf";
   };
-  nativeBuildInputs = [ pythonPackages.setuptools_scm ];
-  propagatedBuildInputs = with pythonPackages; [ pyyaml six jinja2 cerberus11 ];
+  nativeBuildInputs = [ setuptools_scm ];
+  propagatedBuildInputs = [ pyyaml six jinja2 cerberus_1_1 ];
 
   checkPhase = ''
-    ${pythonPackages.python.interpreter} -m unittest discover
+    ${python.interpreter} -m unittest discover
   '';
 
   meta = with stdenv.lib; {