title: How to add order_by to the custom serializer field in django rest framework
body: <p><strong>Serializer:</strong></p>
  
  <pre><code>class RequestSerializer(serializers.ModelSerializer):
  
      travel_date = serializers.SerializerMethodField(method_name='get_traveldate')
      guests = serializers.SerializerMethodField(method_name='get_num_of_guests')
      cost = serializers.SerializerMethodField(method_name='get_invoice_cost')
      status = serializers.SerializerMethodField(method_name='get_request_status')
  
      class Meta:
          model = Request
          fields = (guests, cost,)
  
  
  class BookingView(generics.ListApiView):
  
       serializer_class = RequestSerializer
       model = serializer_class.Meta.model
       paginate_by = 15
       filter_fields = ('costs', 'guests')
  
       def get_queryset(self):
          req_dict = self.request.query_params
          client = int(req_dict.get('client'))
          start_date = date(int(req_dict.get('from_year')), int(req_dict.get('from_month')), 1)
          end_date = get_end_date(int(req_dict.get('to_year')),  int(req_dict.get('to_month')))
          requests = Request.objects.filter(guests__company__id=client, check_in__gte=start_date,
                                            check_out__lte=end_date)
  
          return requests
  </code></pre>