code: public void setOption(String optName, Object optValue) {
          if (optValue == null) {
              m_options.remove(optName);
          } else {
              m_options.put(optName, optValue);
          }
      }
docs: Set the given option. If the option was previously defined, the value is
  overwritten. If the given value is null, the existing option is removed.
  
  @param optName   Option name.
  @param optValue  Option value, which may be a String or Map&lt;String,Object&gt;.