old_contents: from contentcuration.models import *    # TODO: Change this later?
  from rest_framework import serializers
  from rest_framework_bulk import BulkListSerializer, BulkSerializerMixin
  
  class LicenseSerializer(serializers.ModelSerializer):
      class Meta: 
          model = License
          fields = ('license_name', 'exists', 'id')
  
  class ChannelSerializer(serializers.ModelSerializer):
      class Meta:
          model = Channel
          fields = ('name', 'description', 'editors', 'id', 'draft', 'clipboard', 'deleted', 'published','channel_id')
  
  class TopicTreeSerializer(serializers.ModelSerializer):
      class Meta:
          model = TopicTree
          fields = ('name', 'channel', 'root_node', 'id')
  
  class FileSerializer(serializers.ModelSerializer):
      content_copy = serializers.FileField(use_url=False)
   
      def get(*args, **kwargs):
           return super.get(*args, **kwargs)
      class Meta:
          model = File
          fields = ('checksum', 'extension', 'file_size', 'content_copy', 'id', 'available', 'format')
  
  class FormatPresetSerializer(serializers.ModelSerializer):
     # files = FileSerializer(many=True, read_only=True)
  
     class Meta:
          model = Format
          fields = ('id', 'readable_name', 'multi_language', 'supplementary', 'order', 'kind', 'allowed_formats')
  
  class ContentNodeSerializer(BulkSerializerMixin, serializers.ModelSerializer):
      children = serializers.PrimaryKeyRelatedField(many=True, read_only=True)
      preset = FormatPresetSerializer(many=True, read_only=True)
  
      class Meta:
          model = ContentNode
          fields = ('title', 'published', 'total_file_size', 'id', 'description', 'published',
                    'sort_order', 'license_owner', 'license', 'kind', 'children', 'parent', 'content_id',
                    'preset', 'original_filename')
  
  class TagSerializer(serializers.ModelSerializer):
     class Meta:
      model = ContentTag
      fields = ('tag_name', 'tag_type', 'id') 
  
  class ExerciseSerializer(serializers.ModelSerializer):
      class Meta:
          model = Exercise
          fields = ('title', 'description', 'id')
  
  class AssessmentItemSerializer(BulkSerializerMixin, serializers.ModelSerializer):
      exercise = serializers.PrimaryKeyRelatedField(queryset=Exercise.objects.all())
  
      class Meta:
          model = AssessmentItem
          fields = ('question', 'type', 'answers', 'id', 'exercise')
          list_serializer_class = BulkListSerializer
  
new_contents: from contentcuration.models import *    # TODO: Change this later?
  from rest_framework import serializers
  from rest_framework_bulk import BulkListSerializer, BulkSerializerMixin
  
  class LicenseSerializer(serializers.ModelSerializer):
      class Meta: 
          model = License
          fields = ('license_name', 'exists', 'id')
  
  class ChannelSerializer(serializers.ModelSerializer):
      class Meta:
          model = Channel
          fields = ('name', 'description', 'editors', 'id', 'draft', 'clipboard', 'deleted', 'published','channel_id')
  
  class TopicTreeSerializer(serializers.ModelSerializer):
      class Meta:
          model = TopicTree
          fields = ('name', 'channel', 'root_node', 'id')
  
  class FileSerializer(serializers.ModelSerializer):
      content_copy = serializers.FileField(use_url=False)
   
      def get(*args, **kwargs):
           return super.get(*args, **kwargs)
      class Meta:
          model = File
          fields = ('id', 'checksum', 'file_size', 'content_copy', 'contentmetadata', 'file_format', 'preset', 'lang')
  
  class FormatPresetSerializer(serializers.ModelSerializer):
     # files = FileSerializer(many=True, read_only=True)
  
     class Meta:
          model = FormatPreset
          fields = ('id', 'readable_name', 'multi_language', 'supplementary', 'order', 'kind', 'allowed_formats')
  
  class ContentNodeSerializer(BulkSerializerMixin, serializers.ModelSerializer):
      children = serializers.PrimaryKeyRelatedField(many=True, read_only=True)
      preset = FormatPresetSerializer(many=True, read_only=True)
  
      class Meta:
          model = ContentNode
          fields = ('title', 'published', 'total_file_size', 'id', 'description', 'published',
                    'sort_order', 'license_owner', 'license', 'kind', 'children', 'parent', 'content_id',
                    'preset', 'original_filename')
  
  class TagSerializer(serializers.ModelSerializer):
     class Meta:
      model = ContentTag
      fields = ('tag_name', 'tag_type', 'id') 
  
  class ExerciseSerializer(serializers.ModelSerializer):
      class Meta:
          model = Exercise
          fields = ('title', 'description', 'id')
  
  class AssessmentItemSerializer(BulkSerializerMixin, serializers.ModelSerializer):
      exercise = serializers.PrimaryKeyRelatedField(queryset=Exercise.objects.all())
  
      class Meta:
          model = AssessmentItem
          fields = ('question', 'type', 'answers', 'id', 'exercise')
          list_serializer_class = BulkListSerializer
  
subject: fix the field names in serializers