def __init__(self, items=[], b=None, err=0.01):
        assert 0.005 <= err < 0.14, 'must 0.005 < err < 0.14'
        if b is None:
            b = int(math.ceil(math.log((1.04 / err) ** 2, 2)))
        self.alpha = self._get_alpha(b)
        self.b = b
        self.m = 1 << b
        self.M = None #array.array('B', [0] * self.m)
        self.threshold = self.m / 20
        self.items = set(items)
        self.mask = (1<<b) -1
        self.big = 1L << (HASH_LEN - b - 1)
        self.big2 = 1L << (HASH_LEN - b - 2)
        self.bitcount_arr = [1L << i for i in range(b + 1 - HASH_LEN)]
dataset/ETHPy150Open douban/dpark/dpark/hyperloglog.py/HyperLogLog.__init__/swapped operands of `-`