What is the change in reversals from 2018 to 2019?
{"Balance at beginning of year": {"2018": -12749, "2019": -13364}, "Charged to cost of sales": {"2018": -2958, "2019": -4748}, "Reversals": {"2018": 723, "2019": 915}, "Utilization of the provision": {"2018": 1978, "2019": 4994}, "Foreign currency translation effect": {"2018": -358, "2019": -324}, "Balance at end of year": {"2018": -13364, "2019": -12527}}
reversals_2019 = df["Reversals"]["2019"]
reversals_2018 = df["Reversals"]["2018"]
answer = reversals_2019 - reversals_2018