anchor.diff:        sha256 = "102mq1qgmla40hhj8mda70inhakdazm9agyah98kq9931scvf0c9";
         stripLen = 2;
         extraPrefix = "opencv_contrib/";
  -    }) ++
  -    # https://github.com/opencv/opencv/pull/13254
  -    lib.optional enablePython (fetchpatch {
  -      url = https://github.com/opencv/opencv/commit/ad35b79e3f98b4ce30481e0299cca550ed77aef0.patch;
  -      sha256 = "0rkvg6wm5fyncszfpd83wa4lvsb8srvk21r1jcld758i4f334sws";
       });
   
     # This prevents cmake from using libraries in impure paths (which
  
positive.code: }:
  
  let
    version = "4.0.0";
  
    src = fetchFromGitHub {
      owner  = "opencv";
      repo   = "opencv";
      rev    = version;
      sha256 = "1r2hszm4044dfx65wv69rcs419jjd7bqllhnpcwk3n28f5ahln50";
    };
  
    contribSrc = fetchFromGitHub {
      owner  = "opencv";
      repo   = "opencv_contrib";
      rev    = version;
      sha256 = "1g4pzw7hv1v9jp1nrqjxqwpi1byl3mxkj6w6ibq6ydsn0138p66z";
    };
  
  
negative.code:     cp --no-preserve=mode -r "${contribSrc}/modules" "$NIX_BUILD_TOP/source/opencv_contrib"
    '';
  
    patches =
      # Fixes issue: https://github.com/opencv/opencv_contrib/issues/1923
      # PR: https://github.com/opencv/opencv_contrib/pull/1913
      lib.optional buildContrib (fetchpatch {
  