old_contents: import msgpack
  import decimal
  import datetime
  
  from rest_framework.renderers import BaseRenderer
  
  
  class MessagePackEncoder(object):
  
      def encode(self, obj):
          if isinstance(obj, datetime.datetime):
              return {'__class__': 'datetime', 'as_str': obj.isoformat()}
          elif isinstance(obj, datetime.date):
              return {'__class__': 'date', 'as_str': obj.isoformat()}
          elif isinstance(obj, datetime.time):
              return {'__class__': 'time', 'as_str': obj.isoformat()}
          elif isinstance(obj, decimal.Decimal):
              return {'__class__': 'decimal', 'as_str': str(obj)}
          else:
              return obj
  
  
  class MessagePackRenderer(BaseRenderer):
      """
      Renderer which serializes to MessagePack.
      """
  
      media_type = 'application/msgpack'
      format = 'msgpack'
  
      def render(self, data, accepted_media_type=None, renderer_context=None):
          """
          Renders *obj* into serialized MessagePack.
          """
          if data is None:
              return ''
          return msgpack.packb(data, default=MessagePackEncoder().encode)
  
new_contents: import msgpack
  import decimal
  import datetime
  
  from rest_framework.renderers import BaseRenderer
  
  
  class MessagePackEncoder(object):
  
      def encode(self, obj):
          if isinstance(obj, datetime.datetime):
              return {'__class__': 'datetime', 'as_str': obj.isoformat()}
          elif isinstance(obj, datetime.date):
              return {'__class__': 'date', 'as_str': obj.isoformat()}
          elif isinstance(obj, datetime.time):
              return {'__class__': 'time', 'as_str': obj.isoformat()}
          elif isinstance(obj, decimal.Decimal):
              return {'__class__': 'decimal', 'as_str': str(obj)}
          else:
              return obj
  
  
  class MessagePackRenderer(BaseRenderer):
      """
      Renderer which serializes to MessagePack.
      """
  
      media_type = 'application/msgpack'
      format = 'msgpack'
      render_style = 'binary'
      charset = None
  
      def render(self, data, media_type=None, renderer_context=None):
          """
          Renders *obj* into serialized MessagePack.
          """
          if data is None:
              return ''
          return msgpack.packb(data, default=MessagePackEncoder().encode)
  
subject: Update renderers.py to the current version of DRF