@CalcMgrAddDatePart
Purpose:
Adds a specified number of years/months/days/weeks to the date that is in the YYYYMMDD
format. The "date_part" can be one of the following: "day", "month", "week", "year"
Syntax:
Java Class: com.hyperion.calcmgr.common.cdf.CalendarFunctions.addDatePart(int,String,int)
CDF Spec: @CalcMgrAddDatePart(date,date_part, amountToAdd)