{
     packageOverrides = pkgs: rec {
       # Upgrade chromedriver version
       chromedriver = pkgs.stdenv.lib.overrideDerivation pkgs.chromedriver (oldAttrs: {
         name = "chromedriver_linux64-2.27";
         version = "2.27";
         src = fetchurl {
           url = "http://chromedriver.storage.googleapis.com/2.27/chromedriver_linux64.zip";
           sha256 = "11nq06d131y4wmf3drm0yk502d2xc6n5qy82cg88rb9nqd2lj41k";
         };
         patches = [];
       });
     };
}