anchor.diff:      persim
     ];
   
  -  checkPhase = ''
  +  checkInputs = [
  +    pytestCheckHook
  +  ];
  +
  +  preCheck = ''
       # specifically needed for darwin
       export HOME=$(mktemp -d)
       mkdir -p $HOME/.matplotlib
       echo "backend: ps" > $HOME/.matplotlib/matplotlibrc
  -
  -    pytest
     '';
   
     meta = with lib; {
  
positive.code: { lib
  , buildPythonPackage
  , fetchPypi
  , pythonOlder
  , cython
  
negative.code:     sha256 = "335112a0f94532ccbe686db7826ee8d0714b32f65891abf92c0a02f3cb0fc5fd";
    };
  
    patches = [
      (fetchpatch {
        url = "https://github.com/scikit-tda/ripser.py/commit/4baa248994cee9a65d710fac91809bad8ed4e5f1.patch";
        sha256 = "sha256-J/nxMOGOUiBueojJrUlAaXwktHDploYG/XL8/siF2kY=";
      })
    ];
  
    propagatedBuildInputs = [
  