This function should only be used when performing aggregations.
CHMT(var, data, year = "Year")
The variables that require to be sanitized.
The data frame which contains the data
The column which correspond to the year.
We decide to use the smaller subsets in the regional level because weighting variable may not exist for other variables for the larger subsets.
The function only work for FAOST_CODE, if the country coding system is not in FAOST_CODE then use the translateCountryCode function to translate it.