pythonPackages.cryptacular: disable on the current Pythons

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

@@ -1,4 +1,4 @@
-{ stdenv, buildPythonPackage, fetchPypi
+{ stdenv, buildPythonPackage, fetchPypi, isPy27, pythonAtLeast
 , coverage, nose, pbkdf2 }:
 
 buildPythonPackage rec {
@@ -16,6 +16,10 @@ buildPythonPackage rec {
   # TODO: tests fail: TypeError: object of type 'NoneType' has no len()
   doCheck = false;
 
+  # Python >=2.7.15, >=3.6.5 are incompatible:
+  # https://bitbucket.org/dholth/cryptacular/issues/11
+  disabled = isPy27 || pythonAtLeast "3.6";
+
   meta = with stdenv.lib; {
     maintainers = with maintainers; [ domenkozar ];
   };