anchor.diff:      "lz4"
       "lz4.block"
       "lz4.frame"
  +    "lz4.stream"
     ];
   
     checkInputs = [
  
positive.code:     psutil
    ];
  
    # leave build directory, so the installed library gets imported
    preCheck = ''
      pushd tests
    '';
  
    postCheck = ''
      popd
    '';
  
    meta = with lib; {
  
negative.code: , buildPythonPackage
  , fetchFromGitHub
  , pythonOlder
  , python
  
  # native inputs
  , pkgconfig
  