| 
  Initialize an CacheFetcher object.| __init__(self,
        cache,
        address,
        item_freshness_period,
        item_expiration_period,
        item_purge_period,
        object_handler,
        error_handler,
        timeout_handler,
        timeout_period,
        backup_state=None)
    (Constructor)
 | source code |  
    Parameters:
        cache(Cache) - cache object which created this fetcher.address(any hashable) - requested item address.item_freshness_period(timedelta) - freshness period for the requested item.item_expiration_period(timedelta) - expiration period for the requested item.item_purge_period(timedelta) - purge period for the requested item.object_handler(callable(address, value, state)) - function to be called after the item is fetched.error_handler(callable(address, error_data)) - function to be called on error.timeout_handler(callable(address)) - function to be called on timeouttimeout_period(timedelta) - timeout interval.backup_state(bool) - when notNoneand the fetch fails than an
object from cache of at least this state will be passed to theobject_handler. If such object is not available, thenerror_handleris called. |