old_contents: from django.contrib.contenttypes.models import ContentType
  
  from rest_framework import serializers
  
  from extras.models import CF_TYPE_SELECT, CustomField, CustomFieldChoice
  
  
  #
  # Custom fields
  #
  
  class CustomFieldSerializer(serializers.BaseSerializer):
      """
      Extends ModelSerializer to render any CustomFields and their values associated with an object.
      """
  
      def to_representation(self, manager):
  
          # Initialize custom fields dictionary
          data = {f.name: None for f in self.parent._custom_fields}
  
          # Assign CustomFieldValues from database
          for cfv in manager.all():
              if cfv.field.type == CF_TYPE_SELECT:
                  data[cfv.field.name] = CustomFieldChoiceSerializer(cfv.value).data
              else:
                  data[cfv.field.name] = cfv.value
  
          return data
  
  
  class CustomFieldModelSerializer(serializers.ModelSerializer):
      custom_fields = CustomFieldSerializer(source='custom_field_values')
  
      def __init__(self, *args, **kwargs):
  
          super(CustomFieldModelSerializer, self).__init__(*args, **kwargs)
  
          # Cache the list of custom fields for this model
          content_type = ContentType.objects.get_for_model(self.Meta.model)
          self._custom_fields = CustomField.objects.filter(obj_type=content_type)
  
  
  class CustomFieldChoiceSerializer(serializers.ModelSerializer):
  
      class Meta:
          model = CustomFieldChoice
          fields = ['id', 'value']
new_contents: from django.contrib.contenttypes.models import ContentType
  
  from rest_framework import serializers
  
  from extras.models import CF_TYPE_SELECT, CustomField, CustomFieldChoice
  
  
  #
  # Custom fields
  #
  
  class CustomFieldSerializer(serializers.BaseSerializer):
      """
      Extends ModelSerializer to render any CustomFields and their values associated with an object.
      """
  
      def to_representation(self, manager):
  
          # Initialize custom fields dictionary
          data = {f.name: None for f in self.parent._custom_fields}
  
          # Assign CustomFieldValues from database
          for cfv in manager.all():
              if cfv.field.type == CF_TYPE_SELECT:
                  data[cfv.field.name] = CustomFieldChoiceSerializer(cfv.value).data
              else:
                  data[cfv.field.name] = cfv.value
  
          return data
  
  
  class CustomFieldModelSerializer(serializers.ModelSerializer):
      custom_fields = CustomFieldSerializer(source='custom_field_values')
  
      def __init__(self, *args, **kwargs):
  
          super(CustomFieldModelSerializer, self).__init__(*args, **kwargs)
  
          # Cache the list of custom fields for this model
          content_type = ContentType.objects.get_for_model(self.Meta.model)
          self._custom_fields = CustomField.objects.filter(obj_type=content_type)
  
  
  class CustomFieldChoiceSerializer(serializers.ModelSerializer):
  
      class Meta:
          model = CustomFieldChoice
          fields = ['id', 'value']
  
subject: Make CI happy