old_contents: from rest_framework.serializers import Serializer
  from rest_framework.fields import URLField, CharField, DateTimeField
  
  
  class CassandraAdventureSerializer(Serializer):
      adventure_id = URLField(format='hex_verbose')
      adventure_desc = CharField()
      last_modified = DateTimeField()
new_contents: from rest_framework.serializers import Serializer
  from rest_framework.fields import UUIDField, CharField, DateTimeField
  
  
  class CassandraAdventureSerializer(Serializer):
      adventure_id = UUIDField(format='hex_verbose')
      adventure_desc = CharField()
      last_modified = DateTimeField()
  
subject: add CassandraAdventuresSerializer