def kthPrimeNumber_error(self, k):
        """
        heap and queue

        Erroneous on re-appending the next items on the same queue
        Example of errors: 45 is repeated, 45 = 3*3*5 and 45 = 3*5*3

        :param k:
        :return:
        """
        import heapq

        h1 = QueueNode(3)
        h2 = QueueNode(5)
        h3 = QueueNode(7)

        heap = [h1, h2, h3]
        heapq.heapify(heap)

        for cnt in xrange(1-k):
            h = heapq.heappop(heap)
            if h == h1:
                for i in [3, 5, 7]:
                    h1.q.append(i*h1.val)

                h1.next()
                heapq.heappush(heap, h1)
            elif h == h2:
                for i in [5, 7]:
                    h2.q.append(i*h2.val)

                h2.next()
                heapq.heappush(heap, h2)
            else:
                for i in [7]:
                    h3.q.append(i*h3.val)

                h3.next()
                heapq.heappush(heap, h3)

        return heapq.heappop(heap).val
dataset/ETHPy150Open algorhythms/LintCode/Kth Prime Number.py/Solution.kthPrimeNumber_error/swapped operands of `-`