Catching 'NoneType' exceptions in the work with DateTimeFields
I have the following views.py code.
now_time = datetime.datetime.now()
for r in requests:
hmt = r.date_of_notification - now_time
if hmt <= datetime.timedelta(days = 1):
r.time_action_status = 'stactio开发者_Python百科n_day'
else:
r.time_action_status = 'non_staction_day'
Sometimes I get an error, because some date_of_notification in request is empty(NoneType):
TypeError: unsupported operand type(s) for -: 'NoneType' and 'datetime.timedelta'
models.py:
date_of_notification = models.DateTimeField(blank=True, null=True)
What kind of validation for r.date_of_notification
should I use, to avoid mistakes?
if r.date_of_notification is not None:
do_something_useful()
else:
field_is_null()
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