code: public FormInputHandler setTrafo(final ElementTrafo theSetTrafo) {
  		Fields fields = new Fields(this);
  		fields.setTrafo = theSetTrafo;
  		return new FormInputHandler(fields);
  	}
docs: Creates a new {@link FormInputHandler} based on this {@link FormInputHandler} using the specified {@link ElementTrafo} for
  transforming the value before it is set.
  
  @param theSetTrafo
  the {@link ElementTrafo} to transform a value before it is set when step mode is {@link StepMode#SET_VALUE}
  @return the new {@link FormInputHandler} instance