code: public final void add (final OperationalTextKey textKey, final String textValue) {
  
          if (textKey == null || textValue == null) { throw new IllegalArgumentException("This is not a valid operation text key."); }
  
          settingsMap.put(textKey, textValue);
      }
docs: Adds a parameter to this <code>SettingsMap</code>.
  
  @param textKey The name of the parameter to add.
  @param textValue The value of the parameter to add.