What would be the change in Allowance for credit loss—loan receivables between 2018 and 2019?
{"Allowance for doubtful accounts": {"July 27, 2019": 136.0, "July 28, 2018": 129.0}, "Percentage of gross accounts receivable": {"July 27, 2019": 2.4, "July 28, 2018": 2.3}, "Allowance for credit losslease receivables .": {"July 27, 2019": 46.0, "July 28, 2018": 135.0}, "Percentage of gross lease receivables (1)": {"July 27, 2019": 1.8, "July 28, 2018": 4.7}, "Allowance for credit lossloan receivables": {"July 27, 2019": 71.0, "July 28, 2018": 60.0}, "Percentage of gross loan receivables": {"July 27, 2019": 1.3, "July 28, 2018": 1.2}}
allowance_2019 = df["Allowance for credit lossloan receivables"]["July 27, 2019"]
allowance_2018 = df["Allowance for credit lossloan receivables"]["July 28, 2018"]
answer = allowance_2019 - allowance_2018