def netmask(self):
        """Return netmask as an integer.

        >>> "%X" % IP('195.185.0.0/16').netmask().int()
        'FFFF0000'
        """

        # TODO: unify with prefixlenToNetmask?
        if self._ipversion == 4:
            locallen = 32 - self._prefixlen
        elif self._ipversion == 6:
            locallen = 128 - self._prefixlen
        else:
            raise ValueError("only IPv4 and IPv6 supported")

        return ((2 ** self._prefixlen) - 1) << locallen
dataset/ETHPy150Open fp7-ofelia/ocf/ofam/src/src/foamext/IPy.py/IPint.netmask/original