code: @Deprecated
    public static FileSystem getProxiedFileSystemUsingKeytab(@NonNull final String userNameToProxyAs,
        final String superUserName, final Path superUserKeytabLocation, final URI fsURI, final Configuration conf)
        throws ExecutionException {
      try {
        return getProxiedFileSystemUsingKeytab(userNameToProxyAs, superUserName, superUserKeytabLocation, fsURI, conf,
            null);
      } catch (IOException ioe) {
        throw new ExecutionException(ioe);
      }
    }
docs: Cached version of {@link ProxiedFileSystemUtils#createProxiedFileSystemUsingKeytab(String, String, Path, URI, Configuration)}.
  @deprecated use {@link #fromKeytab}.