What was the change in current foreign income tax expense between 2017 and 2018?
{"Current: -- Federal": {"2019": 170, "2018": 223, "2017": "$\u2014"}, "Current: -- State and local": {"2019": 161, "2018": 50, "2017": 62}, "Current: -- Foreign": {"2019": 9966, "2018": 8295, "2017": 4247}, "Current: -- Total current income tax expense from continuing operations": {"2019": 10297, "2018": 8568, "2017": 4309}, "Deferred: -- Federal": {"2019": -43804, "2018": -807, "2017": -6}, "Deferred: -- State and local": {"2019": -773, "2018": -96, "2017": -97}, "Deferred: -- Foreign (1)": {"2019": -5180, "2018": 1467, "2017": 88}, "Deferred: -- Deferred tax expense (benefit) from continuing operations (1)": {"2019": -49757, "2018": 564, "2017": -15}, "Deferred: -- Provision for income tax expense (benefit) (1)": {"2019": -39460, "2018": 9132, "2017": 4294}}
current_foreign_2018 = df["Current: -- Foreign"]["2018"]
current_foreign_2017 = df["Current: -- Foreign"]["2017"]
answer = current_foreign_2018 - current_foreign_2017