docs: public void add(T newValue) {
  		if (this.isSet) {
  			if (!this.isMultiple
  					&& newValue != this.object && (newValue == null || !newValue.equals(this.object))) {
  				this.isMultiple = true;
  				this.object = null;
  			}
  		} else {
  			this.object = newValue;
  			this.isSet = true;
  			this.isMultiple = false;
  		}
  	}