TypeError: '_SentinelObject' object is not callable

I am upgrading my Django application from version 2.2 to 3.2. while upgrading i am facing below issue, i have spent a lot of time to resolve this but didn't get any solution yet.

here's the traceback of issue which i am facing:

  File ".../abc/test.py", line 85, in setUp
    self.MODEL_A.save()
  File ".../abc/models.py", line 470, in save
    super(MODEL_A, self).save(*args, **kwargs)
  File ".../lib/python3.8/site-packages/django/db/models/base.py", line 726, in save
    self.save_base(using=using, force_insert=force_insert,
  File ".../lib/python3.8/site-packages/django/db/models/base.py", line 763, in save_base
    updated = self._save_table(
  File ".../lib/python3.8/site-packages/django/db/models/base.py", line 842, in _save_table
    values = [(f, None, (getattr(self, f.attname) if raw else f.pre_save(self, False)))
  File ".../lib/python3.8/site-packages/django/db/models/base.py", line 842, in <listcomp>
    values = [(f, None, (getattr(self, f.attname) if raw else f.pre_save(self, False)))
  File ".../lib/python3.8/site-packages/django/db/models/fields/__init__.py", line 1396, in pre_save
    value = timezone.now()
TypeError: '_SentinelObject' object is not callable

Any help would be highly appreciated.

Thanks in advance.

Assigning objects which don't support copy.deepcopy() during setUpTestData() is deprecated. Either assign the unit attribute during setUpClass() or setUp(), or add support for deepcopy().

So there might be a code in your test cases like below:

@classmethod
def setUpTestData(cls):
    super(YourTestClassNameHere, cls).setUpTestData()

Change this code as follows:

@classmethod
def setUpClass(cls):
    super(YourTestClassNameHere, cls).setUpClass()

This will resolve your _SentinelObject issues.