Summarize data

Please, check my code!
I forgot to include some kind of readme.st. To test custom command:
python manage.py summarize [date YYYY-MM-DD] [--nodeletion]
If you pass no parameters it summarizes current date minus 15 days (single day and no a 15-days period)
My bad.  I was considering ```output = False``` as a guard.  Guards are an exception to the single exit point:
https://c2.com/cgi/wiki?SingleFunctionExitPoint

Thanks for the link.  Great website.  I'm going to read some of the articles there later :)