anchor.diff:  { stdenv, lib, buildPythonPackage, fetchPypi, makeWrapper, isPy3k
  -, python, twisted, jinja2, zope_interface, sqlalchemy, alembic, python-dateutil
  -, txaio, autobahn, pyjwt, pyyaml, unidiff, treq, txrequests, pypugjs, boto3
  -, moto, mock, lz4, setuptoolsTrial, isort, pylint, flake8, buildbot-worker
  -, buildbot-pkg, buildbot-plugins, parameterized, git, openssh, glibcLocales
  +, python, twisted, jinja2, msgpack, zope_interface, sqlalchemy, alembic
  +, python-dateutil, txaio, autobahn, pyjwt, pyyaml, treq, txrequests, pypugjs
  +, boto3, moto, mock, lz4, setuptoolsTrial, isort, pylint, flake8
  +, buildbot-worker, buildbot-pkg, buildbot-plugins, parameterized, git, openssh
  +, glibcLocales
   , nixosTests
   }:
   
  
positive.code:       autobahn
        pyjwt
        pyyaml
        unidiff
      ]
        # tls
        ++ twisted.extras-require.tls;
  
negative.code:       # core
        twisted
        jinja2
        msgpack
        zope_interface
        sqlalchemy
        alembic
  