mypy: make it usuable as a library

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

@@ -0,0 +1,25 @@
+{ stdenv, fetchPypi, buildPythonPackage, lxml, typed-ast, psutil, isPy3k }:
+
+buildPythonPackage rec {
+  pname = "mypy";
+  version = "0.600";
+
+  # Tests not included in pip package.
+  doCheck = false;
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "1pd3kkz435wlvi9fwqbi3xag5zs59jcjqi6c9gzdjdn23friq9dw";
+  };
+
+  disabled = !isPy3k;
+
+  propagatedBuildInputs = [ lxml typed-ast psutil ];
+
+  meta = with stdenv.lib; {
+    description = "Optional static typing for Python";
+    homepage    = "http://www.mypy-lang.org";
+    license     = licenses.mit;
+    maintainers = with maintainers; [ martingms lnl7 ];
+  };
+}