'Counts items in one or more lists.
**Usage Example**::
feed_counters = ListsStorage(\'user:5\')
unseen_count, unread_count = feed_counters.count(\'unseen\', \'unread\')
unseen_count = feed_counters.count(\'unseen\')
unread_count = feed_counters.count(\'unread\')
: args define which lists\' items to be counted'

def count(self, *args):

    raise NotImplementedError()
