def master_for(self, service_name, redis_class=Redis,
                   connection_pool_class=SentinelConnectionPool, **kwargs):
        """
        Returns a redis client instance for the ``service_name`` master.

        A SentinelConnectionPool class is used to retrive the master's
        address before establishing a new connection.

        NOTE: If the master's address has changed, any cached connections to
        the old master are closed.

        By default clients will be a redis.Redis instance. Specify a
        different class to the ``redis_class`` argument if you desire
        something different.

        The ``connection_pool_class`` specifies the connection pool to use.
        The SentinelConnectionPool will be used by default.

        All other keyword arguments are merged with any connection_kwargs
        passed to this class and passed to the connection pool as keyword
        arguments to be used to initialize Redis connections.
        """
        kwargs['is_master'] = True
        connection_kwargs = dict(self.connection_kwargs)
        connection_kwargs.update(kwargs)
        return redis_class(connection_pool=connection_pool_class(
            service_name, self, **connection_kwargs))

        Returns a redis client instance for the ``service_name`` master.

        A SentinelConnectionPool class is used to retrive the master's
        address before establishing a new connection.

        NOTE: If the master's address has changed, any cached connections to
        the old master are closed.

        By default clients will be a redis.Redis instance. Specify a
        different class to the ``redis_class`` argument if you desire
        something different.

        The ``connection_pool_class`` specifies the connection pool to use.
        The SentinelConnectionPool will be used by default.

        All other keyword arguments are merged with any connection_kwargs
        passed to this class and passed to the connection pool as keyword
        arguments to be used to initialize Redis connections.
        
stackoverflow/venv/lib/python3.6/site-packages/redis/sentinel.py