'Clears one ore more lists.
**Usage Example**::
feed_counters = ListsStorage(\'user:5\')
feed_counters.flush(\'unseen\', \'unread\')
feed_counters.flush(\'unseen\')
feed_counters.flush(\'unread\')
: args define which lists to be cleared'

def flush(self, *args):

    raise NotImplementedError()
