def solve(self, cipher):
        """

        :param cipher: the cipher
        """
        m, A, n, B = cipher

        result = set()  # {} is for dictionary
        hm = {}
        for a in A:
            if a not in hm:
                hm[a] = 1
            else:
                hm[a] += 1

        for b in B:
            if hm not in b or hm[b] <= 0:
                result.add(b)
            else:
                hm[b] -= 1
        result = sorted(list(result))
        return " ".join(map(str, result))
dataset/ETHPy150Open algorhythms/HackerRankAlgorithms/Missing Numbers.py/Solution.solve/swapped operands of `not in`