field 'id' expected a number but got 'slug'

Ошибка в реализации слагирования, в чём - не понимаю

TRACEBACK

Traceback (most recent call last):
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/db/models/fields/__init__.py", line 1772, in get_prep_value
    return int(value)
ValueError: invalid literal for int() with base 10: 'bytovaya-tehnika'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/home/artyomlazovikov/internet_shop/.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/artyomlazovikov/internet_shop/.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/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/views/generic/base.py", line 71, in view
    return self.dispatch(request, *args, **kwargs)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/rest_framework/views.py", line 505, in dispatch
    response = self.handle_exception(exc)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/rest_framework/views.py", line 465, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/rest_framework/views.py", line 476, in raise_uncaught_exception
    raise exc
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/rest_framework/views.py", line 502, in dispatch
    response = handler(request, *args, **kwargs)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/rest_framework/generics.py", line 199, in get
    return self.list(request, *args, **kwargs)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/rest_framework/mixins.py", line 38, in list
    queryset = self.filter_queryset(self.get_queryset())
  File "/home/artyomlazovikov/internet_shop/e_shop/products/views.py", line 37, in get_queryset
    queryset = Product.objects.filter(category=category)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/db/models/query.py", line 904, in filter
    return self._filter_or_exclude(False, *args, **kwargs)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/db/models/query.py", line 923, in _filter_or_exclude
    clone.query.add_q(Q(*args, **kwargs))
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/db/models/sql/query.py", line 1350, in add_q
    clause, _ = self._add_q(q_object, self.used_aliases)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/db/models/sql/query.py", line 1381, in _add_q
    check_filterable=check_filterable,
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/db/models/sql/query.py", line 1311, in build_filter
    condition = self.build_lookup(lookups, col, value)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/db/models/sql/query.py", line 1165, in build_lookup
    lookup = lookup_class(lhs, rhs)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/db/models/lookups.py", line 22, in __init__
    self.rhs = self.get_prep_lookup()
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/db/models/fields/related_lookups.py", line 115, in get_prep_lookup
    self.rhs = target_field.get_prep_value(self.rhs)
  File "/home/artyomlazovikov/internet_shop/.venv/lib/python3.7/site-packages/django/db/models/fields/__init__.py", line 1776, in get_prep_value
    ) from e
ValueError: Field 'id' expected a number but got 'bytovaya-tehnika'.

Модели Product, Category. Отношение M2M.

class Category(models.Model):
    name = models.CharField(max_length=255)
    slug = models.SlugField(max_length=255, db_index=True)
    parental_category = models.ManyToManyField('self', 
                                                blank=True,
                                                verbose_name='Категория-родитель',
                                                )


    def __str__(self):
        return self.name

class Product(models.Model):
    name = models.CharField(max_length=150, db_index=True,
                            verbose_name='Название')
    slug = models.SlugField(max_length=150, db_index=True)
    category = models.ForeignKey(Category, 
                                 related_name='category',
                                 null=True,
                                 blank=True,
                                 verbose_name='Категория',
                                 on_delete=models.SET_NULL,
                                 )

    def __str__(self):
        return self.name

Serializers

class ProductSerializer(serializers.ModelSerializer):
    category = CategorySerializer(many=True, read_only=True)

    class Meta:
        model = Product
        fields = ['id','name','slug',
                  'category']

class CategorySerializer(serializers.ModelSerializer):
    class Meta:
        model = Category
        fields = ['name', 'parental_category']

views

class ProductList(ListAPIView):
    serializer_class = ProductSerializer

    def get_queryset(self):
        queryset = Product.objects.all()
        category = self.kwargs['category_slug']
        if category is not None:
            queryset = Product.objects.filter(category=category)
        return queryset