pythonPackages.dlx: init at 1.0.4

Python implementation of Donald Knuth's Dancing Links (exact cover)
algorithm.

Requirement of qiskit-aqua.

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

@@ -0,0 +1,33 @@
+{ lib
+, buildPythonPackage
+, fetchFromGitHub
+, python
+}:
+
+buildPythonPackage rec {
+  pname = "dlx";
+  version = "1.0.4";
+
+  # untagged releases
+  src = fetchFromGitHub {
+    owner = "sraaphorst";
+    repo = "dlx_python";
+    rev = "02d1ed534df60513095633da07e67a6593b9e9b4";
+    sha256 = "0c6dblbypwmx6yrk9qxp157m3cd7lq3j411ifr3shscv1igxv5hk";
+  };
+
+  # No test suite, so just run an example
+  pythonImportsCheck = [ "dlx" ];
+  # ./examples/design.py requires pyncomb, not in tree
+  checkPhase = ''
+    # example sudoku board from ./examples/sudoku.py
+    ${python.interpreter} ./examples/sudoku.py 3 "070285010008903500000000000500010008010000090900040003000000000002408600090632080"
+  '';
+
+  meta = with lib; {
+    description = "Implementation of Donald Knuth's Dancing Links algorithm";
+    homepage = "https://github.com/sraaphorst/dlx_python";
+    license = licenses.asl20;
+    maintainers = with maintainers; [ drewrisinger ];
+  };
+}

pkgs/top-level/python-packages.nix

@@ -2514,6 +2514,8 @@ in {
 
   discogs_client = callPackage ../development/python-modules/discogs_client { };
 
+  dlx = callPackage ../development/python-modules/dlx { };
+
   dmenu-python = callPackage ../development/python-modules/dmenu { };
 
   dnslib = callPackage ../development/python-modules/dnslib { };