filtrado modelos relacionados dentro de la definición del modelo

Question

Estoy intentando escribir algunos métodos personalizados para mis modelos, pero estoy recibiendo el siguiente error:

Attribute Error: 'ForeignRelatedObjectsDescriptor' object has no attribute all|filter

Esto sucede cuando corro este código:

 
chore = Chore(name='Laundry') 
chore.schedule_set.create(week_day='monday', time_due='17:30:00') 
chore.scheduled() 

¿alguien tiene algún consejo sobre cómo hacer este trabajo o lo que podría hacer falta? Revisé los documentos de Django pero parece que solo cubren los usos más básicos de los modelos.

models.py:

 
from django.db import models 
from datetime import date, timedelta 

class ChoreManager(models.Manager): 
    def by_day(self, week_day): 
     if week_day == 'today': 
      week_day = date.today().strftime("%A") 

     chores = self.filter(week_day=week_day) 

     if chores.count() > 0: 
      return chores 
     else: 
      return False 

    def today(self): 
     return self.by_day(week_day='today') 

class Chore(models.Model): 
    chores = ChoreManager() 
    name = models.CharField(max_length=50) 
    notes = models.TextField(null=True) 

    def scheduled(self, week_day=None): 
     if week_day is None: 
      schedule_count = Chore.schedule_set.all().count() 
     else: 
      if week_day == 'today': 
       week_day = date.today().strftime("%A") 

      schedule_count = Chore.schedule_set.filter(week_day=week_day).count() 

     if schedule_count > 0: 
      return True 
     else: 
      return False 

    def times_by_day(self, week_day): 
     if self.scheduled() == True: 
      if week_day == 'today': 
       week_day = date.today().strftime("%A") 

      return Chore.schedule_set.filter(week_day=week_day).values('time_due') 
     else: 
      return False 

class Schedule(models.Model): 
    chore = models.ForeignKey('Chore') 
    week_day = models.CharField(max_length=9) 
    time_due = models.TimeField() 

    def mark_complete(self): 
     completed_event = Schedule.completedevent_set.create() 
     completed_event.save() 

    def completed_this_week(self): 
     today = date.today() 
     weekstart = today - timedelta(days=today.weekday()) 
     weekend = weekstart + timedelta(days=7, hours=23, minutes=59, seconds=59) 

     if Schedule.completedevent_set.filter(datetime_completed__gte=weekstart, datetime_completed__lte=weekend).count() > 0: 
      return True 
     else: 
      return False 

class CompletedEvent(models.Model): 
    schedule = models.ForeignKey('Schedule') 
    datetime_completed = models.DateTimeField(auto_now_add=True) 

Answer 1

cambio:

schedule_count = Chore.schedule_set.all().count() 

a:

schedule_count = self.schedule_set.all().count() 

en todas las ocurrencias ..