Function calculate_compound_interest

calculate_compound_interest(
    principal: number,
    apr: number,
    compound: CompoundPeriod,
    months: number,
    digits?: number,
): number
Calculates the future value of the principal amount given the specified rate, the compounding cycle, and the number of months in which the principal is accruing interest using the compound interest formula
Parameters
- principal: number
  the starting principal
- apr: number
  the annual percentage rate
- compound: CompoundPeriod
  the compounding period
- months: number
  the number of months in which the principal is held
- digits: number = 2
  the number of digits to round the result to
Returns number