sonntagsgesicht/dcf ? reverse-engineered prompt

Build me a small Python library for discounted cashflows that feels easy to use in finance work.

I want to be able to create business date schedules, build payment plans for loans, and then turn those into cashflow lists I can add together and value. It should handle simple things like fixed cashflows, amortization, outstanding balances, interest based on a fixed rate, and also floating interest from a forward curve. I’d like a clean way to calculate present value from a discount curve, and it should work nicely with date based schedules and quarterly or monthly payments.

Please include a few examples like an annuity loan with principal, redemption, and interest legs, plus a floating rate version. Make it feel like a real small finance toolkit, with good defaults and readable output. If you need to check current docs for related date or curve helpers, look them up online.