code: public static <D extends Comparable> DateTimeExpression<D> dateadd(DatePart unit, DateTimeExpression<D> date, int amount) {
          return Expressions.dateTimeOperation(date.getType(), DATE_ADD_OPS.get(unit), date, ConstantImpl.create(amount));
      }
docs: Create a dateadd(unit, date, amount) expression
  
  @param unit date part
  @param date date
  @param amount amount
  @return converted date