def compound_interest(principal, annual_rate, years):
return principal * (<NUM_LIT:1> + <NUM_LIT> * annual_rate) ** years<EOL>
Returns the future value of money invested at an annual
interest rate, compounded annually for a given number of years.

Args:
    principal: The beginning ammount of money invested

    annual_rate: The interest rate paid out

    years: The number of years invested

Returns:
    A basic calculation of compound interest.