def    fvs(pv, i, n):
    """ This function is for the future value of money
    over a period of time using simple interest.
    pv = Initial Investment (1000)
    i = interest rate as decimal (.0675)
    n = the number of periods (20)
    Example: fv(1000, .0675, 20)
    """
    return pv * i * n