python - Django AttributeError: 'str' オブジェクトに属性 'tzinfo' がありません

Question

データベースからすべてのオブジェクトを取得しようとすると、次のコードでこのエラーが発生します。

data1 = Data.objects.all()
for dataset in data1:

これが私のモデルです：

class Data(models.Model):
id = models.AutoField(db_column='ID', primary_key=True)  # Field name made lowercase.
path = models.TextField(db_column='Path')  # Field name made lowercase.
username = models.ForeignKey('Users', models.DO_NOTHING, db_column='Username')  # Field name made lowercase.
datatype = models.CharField(db_column='Datatype', max_length=20, blank=True, null=True)  # Field name made lowercase.
filesize = models.FloatField(db_column='Filesize', blank=True, null=True)  # Field name made lowercase.
creationdate = models.DateTimeField(db_column='CreationDate')  # Field name made lowercase.
modificationdate = models.DateTimeField(db_column='ModificationDate')  # Field name made lowercase.
diskname = models.CharField(db_column='Diskname', max_length=100, blank=True, null=True)  # Field name made lowercase.

class Meta:
    managed = False
    db_table = 'Data'

完全なエラー メッセージは次のとおりです。

    Internal Server Error: /files/
Traceback (most recent call last):
  File "/home/pi/.local/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/home/pi/.local/lib/python3.7/site-packages/django/core/handlers/base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/pi/.local/lib/python3.7/site-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/pi/.local/lib/python3.7/site-packages/django/views/decorators/cache.py", line 31, in _cache_controlled
    response = viewfunc(request, *args, **kw)
  File "/home/pi/.local/lib/python3.7/site-packages/django/contrib/auth/decorators.py", line 21, in _wrapped_view
    return view_func(request, *args, **kwargs)
  File "/home/pi/MakMakula/FileManager/app/views.py", line 57, in index
    for dataset in data1:
  File "/home/pi/.local/lib/python3.7/site-packages/django/db/models/query.py", line 276, in __iter__
    self._fetch_all()
  File "/home/pi/.local/lib/python3.7/site-packages/django/db/models/query.py", line 1261, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "/home/pi/.local/lib/python3.7/site-packages/django/db/models/query.py", line 74, in __iter__
    for row in compiler.results_iter(results):
  File "/home/pi/.local/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1095, in apply_converters
    value = converter(value, expression, connection)
  File "/home/pi/.local/lib/python3.7/site-packages/django/db/backends/mysql/operations.py", line 265, in convert_datetimefield_value
    value = timezone.make_aware(value, self.connection.timezone)
  File "/home/pi/.local/lib/python3.7/site-packages/django/utils/timezone.py", line 270, in make_aware
    return timezone.localize(value, is_dst=is_dst)
  File "/home/pi/.local/lib/python3.7/site-packages/pytz/__init__.py", line 237, in localize
    if dt.tzinfo is not None:
AttributeError: 'str' object has no attribute 'tzinfo'
[02/Jun/2020 10:43:44] "GET /files/ HTTP/1.1" 500 110853

なぜこれが出てくるのか、誰にもアイデアがありますか？