What is the change in the Software development costs from 2018 to 2019?
{"Software development costs": {"2019": 428641, "2018": 317637}, "Less: accumulated amortization": {"2019": -184712, "2018": -107977}, "Software development costs, net": {"2019": 243929, "2018": 209660}}
software_development_cost_2019 = df["Software development costs"]["2019"]
software_development_cost_2018 = df["Software development costs"]["2018"]
answer = software_development_cost_2019 - software_development_cost_2018