anchor.diff:  , stdenv
   , bokeh
   , buildPythonPackage
  -, fetchpatch
   , fetchFromGitHub
   , fsspec
   , pytestCheckHook
  
positive.code: 
    dontUseSetuptoolsCheck = true;
  
    patches = [
      # dask dataframe cannot be imported in sandboxed builds
      # See https://github.com/dask/dask/pull/7601
      (fetchpatch {
        url = "https://github.com/dask/dask/commit/9ce5b0d258cecb3ef38fd844135ad1f7ac3cea5f.patch";
        sha256 = "sha256-1EVRYwAdTSEEH9jp+UOnrijzezZN3iYR6q6ieYJM3kY=";
        name = "fix-dask-dataframe-imports-in-sandbox.patch";
      })
    ];
  
    postPatch = ''
      # versioneer hack to set version of github package
      echo "def get_versions(): return {'dirty': False, 'error': None, 'full-revisionid': None, 'version': '${version}'}" > dask/_version.py
  
negative.code: 
  buildPythonPackage rec {
    pname = "dask";
    version = "2021.06.1";
    disabled = pythonOlder "3.5";
  
    src = fetchFromGitHub {
      owner = "dask";
      repo = pname;
      rev = version;
      sha256 = "sha256-wrUqLSmlKhd0NSjWBwbow8aX53ZBTgl2n4lEmvxC3bs=";
    };
  
    propagatedBuildInputs = [
  