anchor.diff:    pname = "natsort";
     version = "5.2.0";
   
  -  buildInputs = [
  +  checkInputs = [
       hypothesis
       pytestcache
  -    pytestcov
       pytestflakes
       pytestpep8
       pytest
  
positive.code: { lib
  , buildPythonPackage
  , pythonOlder
  , isPy35
  , isPy36
  , fetchPypi
  , hypothesis
  , pytestcache
  , pytestcov
  , pytestflakes
  , pytestpep8
  , pytest
  
negative.code:   # testing based on project's tox.ini
    checkPhase = ''
      pytest --doctest-modules natsort
      pytest --flakes --pep8
    '';
  
    meta = {
  