@staticmethod
    def cmp(a, b):
        """
        :type a: Interval
        :type b: Interval
        """
        if a.start != b.start:
            return b.start-a.start
        else:
            return a.end-b.end
dataset/ETHPy150Open algorhythms/LintCode/Number of Airplanes in the Sky.py/Solution.cmp/swapped operands of `-`