Convert discount_factors to a tensor before using them to calculate the discount_rates in option_price(). Correct the doc string explanation of the default values for discount_factor in option_price().
Convert discount_factors to a tensor before using them to calculate the discount_rates in option_price().
Correct the doc string explanation of the default values for discount_factor in option_price().

PiperOrigin-RevId: 343498636

google/tf-quant-finance,google/tf-quant-finance