Django rest how to show hierarchical data in get api response

I am getting the category id for GET request but I want to show text in hierarchical structure like child1 → child → child3

my expected response will be look like this

'category': 'child1 -> child -> child3'

now getting response like this

'category': 1

somethings look like that my model where it show category name on hierarchical order enter image description here

my category_model

class Product_category(models.Model):
      domain = models.CharField(max_length=250)
      parent_category = models.ForeignKey('self',on_delete=models.CASCADE,null=True, blank=True)
      category_name = models.CharField(max_length=200,null=True,blank=True,)
      category_icon = models.ImageField(upload_to=dynamic_icon_upload_path,blank=True,null=True)

      def get_hierarchical_name(self):
        if self.parent_category:
            return f"{self.parent_category.get_hierarchical_name()}->{self.category_name}"
            return f"{self.category_name}"

      def __str__(self):
        return self.get_hierarchical_name()

my product model

class Product(models.Model):
    title = models.CharField(max_length=200,blank=True,null=True)
    category  = models.ForeignKey(Product_category,blank=True,null=True,on_delete=models.CASCADE)

my serilizer

class ParentProductSerializer(serializers.ModelSerializer):
       class Meta:
        model = Product
         fields = ['category',...others product fields]

see the screenshot where right now I am getting id instated for hierarchical text enter image description here

You probably want to add :

class ParentProductSerializer(serializers.ModelSerializer):
    category = serializers.CharField(source="category.get_hierarchical_name", read_only=True)
    class Meta:

See Serializers - Django REST framework and Serializer fields - Django REST framework.