old_contents: from marshmallow import Schema, fields
  
  from ..models.core import Post
  
  
  class PostSchema(Schema):
      id = fields.Integer()
      title = fields.String()
      body = fields.String()
      is_published = fields.Boolean()
  
      def make_object(self, data):
          return Post(**data)
  
new_contents: from marshmallow import Schema, fields, post_load
  
  from ..models import Post
  
  
  class PostSchema(Schema):
      __model__ = Post
  
      id = fields.Integer()
      title = fields.String()
      body = fields.String()
      is_published = fields.Boolean()
  
      class Meta:
          ordered = True
  
      @post_load
      def make_object(self, data):
          return self.__model__(**data)
  
subject: Fix post schema for latest marshmallow release