@FUNCTION=OPT_ON_OPTIONS
@SYNTAX=OPT_ON_OPTIONS(type_flag,spot,strike1,strike2,time1,time2,rate,cost_of_carry,volatility)
@DESCRIPTION=OPT_ON_OPTIONS models the theoretical price of options on options.
@type_flag is 'cc' for calls on calls, 'cp' for calls on puts, and so on for 'pc', and 'pp'.
@spot is the spot price of the underlying asset.
@strike1 is the strike price at which the option being valued is struck.
@strike2 is the strike price at which the underlying option is struck.
@time1 is the time in years to maturity of the option.
@time2 is the time in years to the maturity of the underlying option.
(@time2 >= @time1).
@rate is the annualized risk-free rate of interest.
@cost_of_carry is the leakage in value of the underlying asset of the underlying option.for common stocks, this would be the dividend yield.
@volatility is the annualized volatility in price of the underlying asset of the underlying option.
@EXAMPLES=
@SEEALSO=OPT_BS, OPT_BS_DELTA, OPT_BS_RHO, OPT_BS_THETA, OPT_BS_GAMMA