anchor.diff:  
   buildPythonPackage rec {
     pname = "pyarrow";
  -  disabled = !isPy3k;
  +  inherit (_arrow-cpp) version src;
   
  -  inherit (_arrow-cpp) version src;
  +  disabled = pythonOlder "3.7";
   
     sourceRoot = "apache-arrow-${version}/python";
   
  -  nativeBuildInputs = [ cmake cython pkg-config setuptools-scm ];
  -  propagatedBuildInputs = [ numpy six cloudpickle scipy fsspec cffi ];
  +  nativeBuildInputs = [
  +    cmake
  +    cython
  +    pkg-config
  +    setuptools-scm
  +  ];
  +
  +  propagatedBuildInputs = [
  +    cffi
  +    cloudpickle
  +    fsspec
  +    numpy
  +    scipy
  +    six
  +  ];
  +
     checkInputs = [
       hypothesis
       pandas
  
positive.code:     "hdfs"
      "json"
      "parquet"
    ] ++ lib.optionals (!stdenv.isDarwin) [ "plasma" ]);
  
    meta = with lib; {
      description = "A cross-language development platform for in-memory data";
  
negative.code:   ARROW_TEST_DATA = lib.optionalString doCheck _arrow-cpp.ARROW_TEST_DATA;
  
    doCheck = true;
  
    dontUseCmakeConfigure = true;
  
    preBuild = ''
  