anchor.diff:  
     checkInputs = [
       hypothesis
  -    pytest
  +    pytestCheckHook
       pytest-localserver
       pytest-subtesthack
     ];
   
  -  patches = [
  -    # Fixes for hypothesis: https://github.com/pimutils/vdirsyncer/pull/779
  -    (fetchpatch {
  -      url = "https://github.com/pimutils/vdirsyncer/commit/22ad88a6b18b0979c5d1f1d610c1d2f8f87f4b89.patch";
  -      sha256 = "0dbzj6jlxhdidnm3i21a758z83sdiwzhpd45pbkhycfhgmqmhjpl";
  -    })
  -  ];
  -
     postPatch = ''
  -    # Invalid argument: 'perform_health_check' is not a valid setting
  -    substituteInPlace tests/conftest.py \
  -      --replace "perform_health_check=False" ""
  -    substituteInPlace tests/unit/test_repair.py \
  -      --replace $'@settings(perform_health_check=False)  # Using the random module for UIDs\n' ""
  +    substituteInPlace setup.py --replace "click>=5.0,<6.0" "click"
     '';
   
  -  checkPhase = ''
  -    make DETERMINISTIC_TESTS=true PYTEST_ARGS="--deselect=tests/system/cli/test_sync.py::test_verbosity" test
  +  preCheck = ''
  +    export DETERMINISTIC_TESTS=true
     '';
  -  # Tests started to fail lately, for any python version even as low as 3.5 but
  -  # if you enable the check, you'll see even severer errors with a higher then
  -  # 3.5 python version. Hence it's marked as broken for higher then 3.5 and the
  -  # checks are disabled unconditionally. As a general end user advice, use the
  -  # normal "unstable" `vdirsyncer` derivation, not this one.
  -  doCheck = false;
  +
  +  disabledTests = [ "test_verbosity" ];
   
     meta = with stdenv.lib; {
       homepage = "https://github.com/pimutils/vdirsyncer";
       description = "Synchronize calendars and contacts";
       license = licenses.mit;
  -    # vdirsyncer (unstable) works with mainline python versions
  -    broken = (pythonAtLeast "3.6");
       maintainers = with maintainers; [ loewenheim ];
     };
   }
  
positive.code: , requests
  , requests_oauthlib # required for google oauth sync
  , atomicwrites
  , milksnake
  , shippai
  , hypothesis
  , pytest
  , pytest-localserver
  , pytest-subtesthack
  , setuptools_scm
  }:
  
  # Packaging documentation at:
  # https://github.com/pimutils/vdirsyncer/blob/0.16.7/docs/packaging.rst
  buildPythonPackage rec {
    version = "0.16.7";
    pname = "vdirsyncer";
    disabled = isPy27;
  
    src = fetchPypi {
      inherit pname version;
      sha256 = "6c9bcfb9bcb01246c83ba6f8551cf54c58af3323210755485fc23bb7848512ef";
    };
  
    propagatedBuildInputs = [
  
negative.code: { stdenv
  , buildPythonPackage
  , fetchPypi
  , isPy27
  , click
  , click-log
  , click-threading
  