new_contents: from core.models import Identity
  from rest_framework import serializers
  from .quota_serializer import QuotaSerializer
  from .allocation_serializer import AllocationSerializer
  from .user_serializer import UserSerializer
  
  
  class IdentitySerializer(serializers.ModelSerializer):
      quota = QuotaSerializer(source='get_quota.__dict__')
      allocation = AllocationSerializer(source='get_allocation.__dict__')
      user = UserSerializer(source='created_by')
  
      class Meta:
          model = Identity
          fields = ('id', 'quota', 'allocation', 'user')
  
subject: add identity serializer