Create the INET type and an Inet adapter.

def _register_inet(self, oid=None, conn_or_curs=None):
        """ Create the INET type and an Inet adapter."""
        from psycopg2 import extensions as _ext
        if not oid:
            oid = 869
        _ext.INET = _ext.new_type((oid, ), "INET",
                lambda data, cursor: data and Inet(data) or None)
        _ext.register_type(_ext.INET, self._con_pg)
        return _ext.INET