gistfile1.py

import datetime

today =  datetime.datetime.now()

income_list = []
outcome_list = []
item_number_list = Item.objects.all().values_list("item_number", flat=True)

for month in range(1,13):
    for n in item_number_list:
        temp = sum(Income.objects.filter(date__year=today.year, date__month="%s" %n).values_list("money",flat=True))
        income_list.append(temp)

for month in range(1,13):
    for n in item_number_list:
       temp = sum((Outcome.objects.filter(date__year=today.year, date__month="%s" %n).values_list("money",flat=True))
       outcome_list.append(temp)