How to use the datetime.timedelta function in DateTime

def test_add_occupied_timewindow(self, alchemy_store, fact, alchemy_fact):
        """
        Make sure that passing a fact with a timewindow that already has a fact raises error.
        """
        fact.start = alchemy_fact.start - datetime.timedelta(days=4)
        fact.end = alchemy_fact.start + datetime.timedelta(minutes=15)
        with pytest.raises(ValueError):
            alchemy_store.facts._add(fact)

frozen_time.tick(datetime.timedelta(seconds=11))

            start = timeit.default_timer()
            with pytest.raises(MessageReceiveTimeout) as error_context:
                core.receive_message('test_expired_message')
            elapsed = timeit.default_timer() - start

            assert 0 < elapsed < 0.1  # This shouldn't actually take 3 seconds, it should be instant
            assert 'expired' in error_context.value.args[0]

            frozen_time.tick(datetime.timedelta(seconds=1))

            request_id = 19
            core.send_message('test_expired_message', request_id, {}, {'test': 'payload'})

            frozen_time.tick(datetime.timedelta(seconds=10))

            start = timeit.default_timer()
            response = core.receive_message('test_expired_message')
            elapsed = timeit.default_timer() - start

            assert 0 < elapsed < 0.1
            assert response[0] == request_id

def get_time_attr_map(t):
    """
                                                       now -> |
                            hour ago -> |
        day ago -> |
    |--------------|--------------------|---------------------|
    """
    now = datetime.datetime.now()
    if t + datetime.timedelta(hours=3) > now:
        return get_map("main_list_white")
    if t + datetime.timedelta(days=3) > now:
        return get_map("main_list_lg")
    else:
        return get_map("main_list_dg")

:return:
            Returns a :class:`datetime.date`
        """
        if not 0 < week < 54:
            raise ValueError('Invalid week: {}'.format(week))

        if not 0 < day < 8:     # Range is 1-7
            raise ValueError('Invalid weekday: {}'.format(day))

        # Get week 1 for the specific year:
        jan_4 = date(year, 1, 4)   # Week 1 always has January 4th in it
        week_1 = jan_4 - timedelta(days=jan_4.isocalendar()[2] - 1)

        # Now add the specific number of weeks and days to get what we want
        week_offset = (week - 1) * 7 + (day - 1)
        return week_1 + timedelta(days=week_offset)

def GetRandomDatetime():
  """Return a datetime in the next week."""
  seconds_offset = random.randint(0, 60 * 60 * 24 * 7)
  dt = datetime.today() + timedelta(seconds=seconds_offset)
  return dt.replace(second=0, microsecond=0)

def do_precip12(ts, ds):
    """Compute the 24 Hour precip at 12 UTC, we do some more tricks though"""
    offset = iemre.daily_offset(ts)
    ets = utc(ts.year, ts.month, ts.day, 12)
    sts = ets - datetime.timedelta(hours=24)
    offset1 = iemre.hourly_offset(sts)
    offset2 = iemre.hourly_offset(ets)
    if ts.month == 1 and ts.day == 1:
        if sts.year >= 1900:
            LOG.warning(
                "p01d_12z  for %s [idx:%s] %s(%s)->%s(%s) SPECIAL",
                ts,
                offset,
                sts.strftime("%Y%m%d%H"),
                offset1,
                ets.strftime("%Y%m%d%H"),
                offset2,
            )
        ncfn = iemre.get_hourly_ncname(ets.year)
        if not os.path.isfile(ncfn):
            LOG.warning("Missing %s", ncfn)

def soon():
    soon = datetime.date.today() + datetime.timedelta(days=30)
    return {'month': soon.month, 'year': soon.year}

# feeds about all legislation that we offer the user to subscribe to
        feeds = [f for f in Feed.get_simple_feeds() if f.category == "federal-bills"]

        # info about bills by status
        groups = [
            (   g[0], # title
                g[1], # text 1
                g[2], # text 2
                "/congress/bills/browse?status=" + ",".join(str(s) for s in g[4]) + "&sort=-current_status_date", # link
               load_bill_status_qs(g[4]).count(), # count in category
               load_bill_status_qs(g[4]).order_by('-current_status_date')[0:6], # top 6 in this category
                )
            for g in bill_status_groups ]

        # legislation coming up
        dhg_bills = Bill.objects.filter(congress=CURRENT_CONGRESS, docs_house_gov_postdate__gt=datetime.datetime.now() - datetime.timedelta(days=10)).filter(docs_house_gov_postdate__gt=F('current_status_date'))
        sfs_bills = Bill.objects.filter(congress=CURRENT_CONGRESS, senate_floor_schedule_postdate__gt=datetime.datetime.now() - datetime.timedelta(days=5)).filter(senate_floor_schedule_postdate__gt=F('current_status_date'))
        coming_up = list((dhg_bills | sfs_bills).order_by('scheduled_consideration_date'))

        # top tracked bills
        top_bills = Feed.objects\
            .filter(feedname__startswith='bill:')\
            .filter(feedname__regex='^bill:[hs][jcr]?%d-' % CURRENT_CONGRESS)
        top_bills = top_bills\
            .annotate(count=Count('tracked_in_lists'))\
            .order_by('-count')\
            .values('feedname', 'count')\
            [0:25]
        top_bills = [(Bill.from_feed(Feed.from_name(bf["feedname"])), bf["count"]) for bf in top_bills]

        # trending bills
        trf = Feed.get_trending_feeds()

def is_newer_than(after, seconds):
    """Return True if after is newer than seconds."""
    if isinstance(after, basestring):
        after = parse_strtime(after).replace(tzinfo=None)
    return after - utcnow() > datetime.timedelta(seconds=seconds)

def func():
            self.high_post = self.high_post + timedelta(hours=self.threshold)