What is the total IT services and hardware between 2017 to 2019?
{"Year ended December 31, -- (dollars in millions)": {"2019": 2019.0, "2018": 2018.0, "2017": 2017.0}, "Entertainment and Communications -- Products and services transferred at a point in time": {"2019": 31.7, "2018": 25.3, "2017": 20.6}, "Entertainment and Communications -- Products and services transferred over time": {"2019": 942.4, "2018": 805.8, "2017": 664.3}, "Entertainment and Communications -- Intersegment revenue": {"2019": 21.6, "2018": 22.3, "2017": 21.2}, "Entertainment and Communications -- Total Entertainment and Communications": {"2019": 995.7, "2018": 853.4, "2017": 706.1}, "IT Services and Hardware -- Products and services transferred at a point in time": {"2019": 138.7, "2018": 142.9, "2017": 80.8}, "IT Services and Hardware -- Products and services transferred over time": {"2019": 423.9, "2018": 404.2, "2017": 300.0}, "IT Services and Hardware -- Intersegment revenue": {"2019": 4.8, "2018": 3.8, "2017": 4.3}, "IT Services and Hardware -- Total IT Services and Hardware": {"2019": 567.4, "2018": 550.9, "2017": 385.1}, "Total Revenue -- Total products and services transferred at a point in time": {"2019": 170.4, "2018": 168.2, "2017": 101.4}, "Total Revenue -- Total products and services transferred over time": {"2019": 1366.3, "2018": 1210.0, "2017": 964.3}, "Total Revenue -- Total revenue": {"2019": 1536.7, "2018": 1378.2, "2017": 1065.7}}
total_it_services_and_hardware_2019 = df["IT Services and Hardware -- Total IT Services and Hardware"]["2019"]
total_it_services_and_hardware_2018 = df["IT Services and Hardware -- Total IT Services and Hardware"]["2018"]
total_it_services_and_hardware_2017 = df["IT Services and Hardware -- Total IT Services and Hardware"]["2017"]
answer = total_it_services_and_hardware_2019 + total_it_services_and_hardware_2018 + total_it_services_and_hardware_2017