Объект ModelBase не повторяется

Question

когда я получаю все профили из базы данных, я получаю следующую ошибку

Traceback (most recent call last):
  File "/home//venv/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/home/venv/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/venv/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/venv/lib/python3.7/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "/home/venv/lib/python3.7/site-packages/django/views/generic/base.py", line 71, in view
    return self.dispatch(request, *args, **kwargs)
  File "/home/venv/lib/python3.7/site-packages/rest_framework/views.py", line 495, in dispatch
    response = self.handle_exception(exc)
  File "/home/venv/lib/python3.7/site-packages/rest_framework/views.py", line 455, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/home/venv/lib/python3.7/site-packages/rest_framework/views.py", line 492, in dispatch
    response = handler(request, *args, **kwargs)
  File "/home/venv/lib/python3.7/site-packages/rest_framework/generics.py", line 241, in get
    return self.list(request, *args, **kwargs)
  File "/home/venv/lib/python3.7/site-packages/rest_framework/mixins.py", line 48, in list
    return Response(serializer.data)
  File "/home/venv/lib/python3.7/site-packages/rest_framework/serializers.py", line 768, in data
    ret = super(ListSerializer, self).data
  File "/home/venv/lib/python3.7/site-packages/rest_framework/serializers.py", line 262, in data
    self._data = self.to_representation(self.instance)
  File "/home/venv/lib/python3.7/site-packages/rest_framework/serializers.py", line 686, in to_representation
    self.child.to_representation(item) for item in iterable
TypeError: 'ModelBase' object is not iterable
[11/Jul/2019 10:15:06] "GET /profile/ HTTP/1.1" 500 24593
Internal Server Error: /profile/

Я легко создаю профиль методом post, но получение всех профилей является проблемой. мой models.py файл

class Profile(TimeModel):
   user = models.OneToOneField('user_accounts.CustomUser', primary_key=True, on_delete=models.CASCADE)
   first_name = models.CharField(max_length=30, null=True)
   last_name = models.CharField(max_length=30, null=True)
   birthdate = models.DateTimeField(null=True)
   image = models.ImageField(upload_to='profile_images', null=True)

   def __str__(self):
      return self.user.email

в serializers.py

class ProfileSerializer(serializers.ModelSerializer):
  user = UserSerializer(read_only=True, source='user.email')
  character = CharacterSerializer()
  category = CategorySerializer()
  birthdate = serializers.DateTimeField(format='%Y-%m-%d')

   class Meta:
     model = Profile
     fields = ['user', 'first_name', 'last_name', 'birthdate', 'gender', 'image', 'category', 'character']

Я посмотрел на некоторые решения, но они не помогли решить их. Кроме того, я добавил

base = (models.Model,) для миграций

ничего не сделал. как я могу решить эту проблему?