What was the change in net income between 2017 and 2018?
{"Net income": {"2019": 95973, "2018": 127980, "2017": 138668}, "Change in financial guarantee liability(1)": {"2019": 16215, "2018": "\u2014", "2017": "\u2014"}, "Transaction expenses(2)": {"2019": 11345, "2018": 2393, "2017": 2612}, "Non-recurring expenses(3)": {"2019": 2804, "2018": "\u2014", "2017": "\u2014"}, "Incremental pro forma tax expense(4)": {"2019": -24768, "2018": -21248, "2017": -54266}, "Adjusted Pro Forma Net Income": {"2019": 101569, "2018": 109125, "2017": 87014}}
net_income_2018 = df["Net income"]["2018"]
net_income_2017 = df["Net income"]["2017"]
answer = net_income_2018 - net_income_2017