def __missing__(self, key):
        if self.default_factory is None:
            raise KeyError(key)
        else:
            ret = self[key] = self.default_factory(name=key)
            return ret
def _genSeq(self):
        self.raw_sequence = random.getrandbits(64)
        parts = []
        while self.raw_sequence:
            parts.append(self.raw_sequence & limit)
            self.raw_sequence >>= 32

        self.sequence = struct.pack('<' + 'L'*len(parts), *parts)
        # struct.unpack('<LL', '\xb1l\x1c\xb1\x11"\x10\xf4')
        return 0