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