TypeError: int() argument must be a string, a bytes-like object or a real number, not 'Category'

 Environment:
 
 
Request Method: GET
Request URL: http://127.0.0.1:8000/api/v1/news_list/
 
Django Version: 4.1.7
Python Version: 3.10.0
Installed Applications:
['rest_framework',
 'news.apps.NewsConfig',
 'django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']
 
 
 
Traceback (most recent call last):
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\django\core\handlers\exception.py", line 56, in inner
    response = get_response(request)
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\django\core\handlers\base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\django\views\decorators\csrf.py", line 55, in wrapped_view
    return view_func(*args, **kwargs)
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\django\views\generic\base.py", line 103, in view
    return self.dispatch(request, *args, **kwargs)
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\rest_framework\views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\rest_framework\views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\rest_framework\views.py", line 480, in raise_uncaught_exception
    raise exc
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\rest_framework\views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "C:\Users\Лариса\PycharmProjects\DRFproj\drfproj\news\views.py", line 15, in get
    return Response({'posts': NewSerializer(new, many=True).data})  # converts a list of values to a list of dicts
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\rest_framework\serializers.py", line 768, in data
    ret = super().data
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\rest_framework\serializers.py", line 253, in data
    self._data = self.to_representation(self.instance)
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\rest_framework\serializers.py", line 686, in to_representation
    return [
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\rest_framework\serializers.py", line 687, in <listcomp>
    self.child.to_representation(item) for item in iterable
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\rest_framework\serializers.py", line 522, in to_representation
    ret[field.field_name] = field.to_representation(attribute)
  File "C:\Users\Лариса\PycharmProjects\DRFproj\venv\lib\site-packages\rest_framework\fields.py", line 916, in to_representation
    return int(value)
 
Exception Type: TypeError at /api/v1/news_list/
Exception Value: int() argument must be a string, a bytes-like object or a real number, not 'Category'

from django.forms import model_to_dict
from django.shortcuts import render
from rest_framework import generics
from .models import New
from .serializers import NewSerializer
from rest_framework.views import APIView
from rest_framework.response import Response
 
 
# view responsible for processing requests
class NewAPIView(APIView):
 
    def get(self, request):
        new = New.objects.all()
        return Response({'posts': NewSerializer(new, many=True).data})  # converts a list of values to a list of dicts
 
    def post(self, request):
        serializer = NewSerializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        serializer.save()
 
        return Response({'post': serializer.data})      # return data about adding article
 
    def put(self, request, *args, **kwargs):
        pk = kwargs.get("pk", None)
        if not pk:
            return Response({"error": "Method PUT is not allowed"})
 
        try:
            instance = New.objects.get(pk=pk)
        except:
            return Response({"error": "Object doesn't exists"})
 
        serializer = NewSerializer(data=request.data, instance=instance)
        serializer.is_valid(raise_exception=True)
        serializer.save()
        return Response({"post": serializer.data})
 
 
    def delete(self, request, *args, **kwargs):
        pk = kwargs.get("pk", None)
        if not pk:
            return Response({"error": "Method DELETE is not allowed"})
 
        try:
            instance = New.objects.get(pk=pk)
            instance.delete()
        except:
            return Response({"error": "Object doesn't exists"})
 
        return Response({"post": "delete post" + str(pk)})
 
# class NewAPIView(generics.ListAPIView):
#    queryset = New.objects.all()
#    serializer_class = NewSerializer

from django.db import models
 
 
class New(models.Model):
    title = models.CharField(max_length=255)
    content = models.TextField(blank=True)
    time_create = models.DateTimeField(auto_now_add=True)
    time_update = models.DateTimeField(auto_now=True)
    is_published = models.BooleanField(default=True)
    cat = models.ForeignKey('Category', on_delete=models.PROTECT, null=False)
 
    def __str__(self):
        return self.title
 
 
class Category(models.Model):
    name = models.CharField(max_length=100, db_index=True)
 
    def __str__(self):
        return self.name

from rest_framework import serializers
from .models import New
 
 
# class NewModel():
#     def __init__(self, title, content):
#         self.title = title
#         self.content = content
 
# serializer responsible for processing data
class NewSerializer(serializers.Serializer):
    title = serializers.CharField(max_length=255),
    content = serializers.CharField()
    time_create = serializers.DateTimeField(read_only=True)
    time_update = serializers.DateTimeField(read_only=True)
    is_published = serializers.BooleanField(default=True)
    cat = serializers.IntegerField()
 
    def create(self, validated_data):
        return New.objects.create(**validated_data)
 
    def update(self, instance, validated_data):
        instance.title = validated_data.get("title", instance.title)
        instance.content = validated_data.get("content", instance.content)
        instance.time_update = validated_data.get("time_update", instance.time_update)
        instance.is_published = validated_data.get("is_published", instance.is_published)
        instance.cat_id = validated_data.get("cat_id", instance.cat_id)
        instance.save()     # save article in the database
        return instance

class IntegerField(Field):
    default_error_messages = {
        'invalid': _('A valid integer is required.'),
        'max_value': _('Ensure this value is less than or equal to {max_value}.'),
        'min_value': _('Ensure this value is greater than or equal to {min_value}.'),
        'max_string_length': _('String value too large.')
    }
    MAX_STRING_LENGTH = 1000  # Guard against malicious string inputs.
    re_decimal = re.compile(r'\.0*\s*$')  # allow e.g. '1.0' as an int, but not '1.2'
 
    def __init__(self, **kwargs):
        self.max_value = kwargs.pop('max_value', None)
        self.min_value = kwargs.pop('min_value', None)
        super().__init__(**kwargs)
        if self.max_value is not None:
            message = lazy_format(self.error_messages['max_value'], max_value=self.max_value)
            self.validators.append(
                MaxValueValidator(self.max_value, message=message))
        if self.min_value is not None:
            message = lazy_format(self.error_messages['min_value'], min_value=self.min_value)
            self.validators.append(
                MinValueValidator(self.min_value, message=message))
 
    def to_internal_value(self, data):
        if isinstance(data, str) and len(data) > self.MAX_STRING_LENGTH:
            self.fail('max_string_length')
 
        try:
            data = int(self.re_decimal.sub('', str(data)))
        except (ValueError, TypeError):
            self.fail('invalid')
        return data
 
    def to_representation(self, value):
        if value is not None:
            return int(value)

cat = serializers.PrimaryKeyRelatedField(many=True, read_only=True)

cat = serializers.PrimaryKeyRelatedField(many=True, read_only=True)