anchor.diff: -{ lib, buildPythonPackage, fetchPypi, isPy27
  -, fetchpatch
  +{ lib
  +, buildPythonPackage
  +, fetchPypi
  +, isPy27
   , pandas
   , pytestCheckHook
   , scikitlearn
  
positive.code:     "show_versions"
      "test_make_imbalanced_iris"
      "test_rusboost[SAMME.R]"
    ];
  
    meta = with lib; {
  
negative.code: 
  buildPythonPackage rec {
    pname = "imbalanced-learn";
    version = "0.8.0";
    disabled = isPy27; # scikit-learn>=0.21 doesn't work on python2
  
    src = fetchPypi {
      inherit pname version;
      sha256 = "0a9xrw4qsh95g85pg2611hvj6xcfncw646si2icaz22haw1x410w";
    };
  
    propagatedBuildInputs = [ scikitlearn ];
    checkInputs = [ pytestCheckHook pandas ];
  