code: public final String remove (final OperationalTextKey textKey) {
  
          if (textKey == null) { throw new NullPointerException(); }
  
          if (!settingsMap.containsKey(textKey)) { throw new IllegalArgumentException("This entry does not exists."); }
  
          return settingsMap.remove(textKey);
      }
docs: Removes the given parameter from this <code>SettingsMap</code>.
  
  @param textKey The name of the parameter.
  @return The value of the removed parameter.