ValueError: day is out of range for month

[Justintime50]

I'm getting the following for the date 2021/05/07 - I ran the following in the repl and was able to reproduce the issue:

>> import calendar
>>> import datetime
>>> y, m, d = dt.year, dt.month, dt.day
>>> dt = datetime.date(2021, 5, 31) - datetime.timedelta(days=360). # this is what the logic does
>>> y, m, d = dt.year, dt.month, dt.day
>>> datetime.date(y, m, calendar.monthrange(y, m)[0])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: day is out of range for mont

Here is the error though:

[Justintime50]

After poking a bit, I can only assume these should have been 365 days instead of 360? This seems to clear it up in the repl:

https://github.com/hacktoolkit/phablytics/blob/master/phablytics/web/metrics/forms.py#L43

[Justintime50]

@jontsai had a chance to check this out?

[jontsai]

I wasn't able to reproduce it exactly, but I think #11 handles this issue, hopefully.