def _ip_int_from_prefix(self, prefixlen=None):
        if prefixlen is None:
            prefixlen = self._prefixlen
        return self._ALL_ONES ^ (self._ALL_ONES >> prefixlen)
test to make sure int16 type numpy scalars are accepted
dataset/ETHPy150Open Exa-Networks/exabgp/lib/exabgp/dep/ipaddress.py/_IPAddressBase._ip_int_from_prefix--crossover with--dataset/ETHPy150Open NeuralEnsemble/python-neo/neo/test/coretest/test_base.py/TestBaseNeoNumpyScalarTypes.test_numpy_scalar_int16