code: public void setParams(final Map<String, String> params) {
      // check "format y" and "format y2"
      String[] y_format_keys = {"format y", "format y2"};
      for(String k : y_format_keys){
        if(params.containsKey(k)){
          params.put(k, URLDecoder.decode(params.get(k)));
        }
      }
      this.params = params;
    }
docs: Sets the global parameters for this plot.
  @param params Each entry is a Gnuplot setting that will be written as-is
  in the Gnuplot script file: {@code set KEY VALUE}.
  When the value is {@code null} the script will instead contain
  {@code unset KEY}.
  <p>
  Special parameters with a special meaning (since OpenTSDB 1.1):
  <ul>
  <li>{@code bgcolor}: Either {@code transparent} or an RGB color in
  hexadecimal (with a leading 'x' as in {@code x01AB23}).</li>
  <li>{@code fgcolor}: An RGB color in hexadecimal ({@code x42BEE7}).</li>
  </ul>