What was the change in revenues from The Cool Pool Limited  from 2017 to 2018?
{"Revenues from fixed rate time charters": {"2017": 485961, "2018": 515324, "2019": 558266}, "Revenues from variable rate time charters": {"2017": "\u2014", "2018": "\u2014", "2019": 64334}, "Revenues from The Cool Pool Limited (GasLog vessels)": {"2017": 38046, "2018": 102253, "2019": 45253}, "Revenues from vessel management services": {"2017": 1222, "2018": 767, "2019": 784}, "Total": {"2017": 525229, "2018": 618344, "2019": 668637}}
revenues_2018 = df["Revenues from The Cool Pool Limited (GasLog vessels)"]["2018"]
revenues_2017 = df["Revenues from The Cool Pool Limited (GasLog vessels)"]["2017"]
answer = revenues_2018 - revenues_2017