code: public static final void removeWriter(String format) {
  		String key = format.toLowerCase();
  		if (JSON.equals(key)) {
  			throw new IllegalArgumentException("Unable to delete the default JSON writer!");
  		}
  		writers.remove(key);
  	}
docs: Deregisters the given format from the registry.
  
  @param format
  name of the format (eg. "custom", "csv", etc.)