'Adds many activities to the feed
Unfortunately we can\'t support the batch interface.
The writes depend on the reads.
Also subsequent writes will depend on these writes.
So no batching is possible at all.
:param activities: the list of activities'

def add_many(self, activities, trim=True, current_activities=None, *args, **kwargs):

    validate_list_of_strict(activities, (self.activity_class, FakeActivity))
    aggregator = self.get_aggregator()
    t = timer()
    if (current_activities is None):
        current_activities = self[:self.merge_max_length]
    msg_format = 'reading    %s    items    took    %s'
    logger.debug(msg_format, self.merge_max_length, t.next())
    (new, changed, deleted) = aggregator.merge(current_activities, activities)
    logger.debug('merge    took    %s', t.next())
    new_aggregated = self._update_from_diff(new, changed, deleted)
    new_aggregated = aggregator.rank(new_aggregated)
    if (trim and (random.random() <= self.trim_chance)):
        self.timeline_storage.trim(self.key, self.max_length)
    return new_aggregated
