programing of finance on Python

IRR calculation: 1) Assume an investment has the following cash flows: -$100, -$50, $50, $70, $100, $90, $20. The first one comes now, the second one in one year, etc. Store in a list. 2) Calculate the NPV if the discount rate is 10%. Do this by creating and calling a function that takes the discount rate and cash flow list as arguments and returns the NPV. 3) Calculate the IRR to the nearest basis point. Consider the IRR solved if that discount rate results in an NPV less than $.01. 4) Print out the answers. 5) You will (probably) use a "for" loop with a "break" statement