class wait_chain(wait_base):
    """Chain two or more waiting strategies.

    If all strategies are exhausted, the very last strategy is used
    thereafter.

    For example::

        @retry(wait=wait_chain(*[wait_fixed(1) for i in range(3)] +
                               [wait_fixed(2) for j in range(5)] +
                               [wait_fixed(5) for k in range(4)))
        def wait_chained():
            print("Wait 1s for 3 attempts, 2s for 5 attempts and 5s
                   thereafter.")
    """

    def __init__(self, *strategies):
        self.strategies = [_compat.wait_func_accept_retry_state(strategy)
                           for strategy in strategies]

@retry(wait=wait_chain(*[wait_fixed(1) for i in range(3)] +  
                               [wait_fixed(2) for j in range(5)] + 
                               [wait_fixed(5) for k in range(4)]))