def updateBits(self, n, m, i, j):
        mask = ((1<<32)-1)-((1<<j+1)-1)+((1<<i)-1)
        ret = (n&mask)+(m<<i)
        return self.twos_comp(ret, 32)
Return a key that will uniquely identify this vpnvX NLRI inside
dataset/ETHPy150Open algorhythms/LintCode/Update Bits.py/Solution.updateBits--crossover with--dataset/ETHPy150Open osrg/ryu/ryu/services/protocols/bgp/info_base/vpn.py/VpnTable._table_key