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: , scipy
  , scikit-learn
  , persim
  , pytest
  }:
  
  buildPythonPackage rec {
  
negative.code: { lib
  , buildPythonPackage
  , fetchpatch
  , fetchPypi
  , pythonOlder
  , cython
  