Use this function wherever you want to have a index based on the financial Monther Order rather then Calander Month Order
This function will return the respective Financial Month Code, when the Calander Month Code is given as input for this function
e.g. For April, The Calander Month Code is '04' where as the Financial Month Code is '01' as all financial years started with April.
Similarly for January the Calander Month Code is '01' whereas the Financial Year Code is '10'