def _create_column_family(self, family, bytes_columns=[], 
                              key_validation_class=TIME_UUID_TYPE):
        '''
        Creates a column family of the name 'family' and sets any of
        the names in the bytes_column list to have the BYTES_TYPE.

        key_validation_class defaults to TIME_UUID_TYPE and could also
        be ASCII_TYPE for md5 hash keys, like we use for 'inbound'
        '''
        sm = SystemManager(random.choice(self.server_list))
        # sys.create_column_family(self.namespace, family, super=False)
        sm.create_column_family(self.namespace, family, super=False,
                key_validation_class = key_validation_class, 
                default_validation_class  = TIME_UUID_TYPE,
                column_name_class = ASCII_TYPE)
        for column in bytes_columns:
            sm.alter_column(self.namespace, family, column, BYTES_TYPE)
        sm.close()
Creates a column family of the name 'family' and sets any of
        the names in the bytes_column list to have the BYTES_TYPE.

        key_validation_class defaults to TIME_UUID_TYPE and could also
        be ASCII_TYPE for md5 hash keys, like we use for 'inbound'