python.pkgs.PyLTI: move expression

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

···
+{ lib
+, buildPythonPackage
+, fetchPypi
+, httplib2
+, oauth
+, oauth2
+, semantic-version
+, flask
+, httpretty
+, oauthlib
+, pyflakes
+, pytest_27
+, pytestcache
+, pytestcov
+, covCore
+, pytestflakes
+, pytestpep8
+, sphinx
+, mock
+, isPy27
+}:
+
+buildPythonPackage rec {
+  pname = "PyLTI";
+  version = "0.4.1";
+
+  disabled = !isPy27;
+
+  # There is no need to fix mock. https://github.com/mitodl/pylti/pull/48
+  postPatch = ''
+    substituteInPlace setup.py --replace "mock==1.0.1" "mock"
+  '';
+
+  propagatedBuildInputs = [ httplib2 oauth oauth2 semantic-version ];
+  checkInputs = [
+    flask httpretty oauthlib pyflakes pytest_27 pytestcache pytestcov covCore
+    pytestflakes pytestpep8 sphinx mock
+  ];
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "076llj10j85zw3zq2gygx2pcfqi9rgcld5m4vq1iai1fk15x60fz";
+  };
+
+  meta = {
+    description = "Implementation of IMS LTI interface that works with edX";
+    homepage = "https://github.com/mitodl/pylti";
+    license = lib.licenses.bsdOriginal;
+    maintainers = with lib.maintainers; [ layus ];
+  };
+}

pkgs/top-level/python-packages.nix

···
     };
   };
 
-  PyLTI = buildPythonPackage rec {
-    version = "0.4.1";
-    name = "PyLTI-${version}";
-
-    disabled = !isPy27;
-
-    # There is no need to fix mock. https://github.com/mitodl/pylti/pull/48
-    postPatch = ''
-      substituteInPlace setup.py --replace "mock==1.0.1" "mock"
-    '';
-
-    propagatedBuildInputs = with self; [ httplib2 oauth oauth2 semantic-version ];
-    buildInputs = with self; [
-      flask httpretty oauthlib pyflakes pytest_27 pytestcache pytestcov covCore
-      pytestflakes pytestpep8 sphinx mock
-    ];
-
-    src = pkgs.fetchurl {
-      url = "mirror://pypi/P/PyLTI/${name}.tar.gz";
-      sha256 = "076llj10j85zw3zq2gygx2pcfqi9rgcld5m4vq1iai1fk15x60fz";
-    };
-
-    meta = {
-      description = "Implementation of IMS LTI interface that works with edX";
-      homepage = "https://github.com/mitodl/pylti";
-      license = licenses.bsdOriginal;
-      maintainers = with maintainers; [ layus ];
-    };
-  };
+  PyLTI = callPackage ../development/python-modules/pylti { };
 
   lmdb = buildPythonPackage rec {
     pname = "lmdb";