code: @Override
  	public void addType(int key, Class<? extends Key<?>> type) throws ConflictingFieldTypeInfoException  {
  		Class<? extends Key<?>> previous = this.schema.put(key, type);
  		if (previous != null && previous != type) {
  			throw new ConflictingFieldTypeInfoException(key, previous, type);
  		}
  	}
docs: --------------------------------------------------------------------------------------------