Django:'ModelForm'对象没有属性

Question

我正在使用Django表单来创建一个新对象，但是我遇到了一些问题。一切正常，但当我提交表单时，出现了一个错误：

"AttributeError at /rutinas/nueva_rutina

'DiaForm' object has no attribute 'ejercicios'"

我在这里读到过很多可能的解决方法，但都不管用。我认为问题出在M2M关系上，但它也可以同时处理两个表单。这是我的档案

型号.py

class Ejercicio(models.Model):
    id = models.AutoField(primary_key=True)
    nombre = models.CharField(max_length=30, default='')
    descripcion = models.TextField(default='')
    gif = models.ImageField(default='')

def __str__(self):
    return self.nombre


class Rutina(models.Model):
     id = models.AutoField(primary_key=True)
     nombre = models.CharField(max_length=30, default='')

def __str__(self):
    return self.nombre

class Dia(models.Model):
    ejercicios = models.ManyToManyField(Ejercicio)
    rutina = models.ForeignKey(Rutina, on_delete=models.CASCADE)

表单.py

class RutinaForm(forms.ModelForm):
    class Meta:
        model = Rutina
        fields = '__all__'
        labels = {
            'nombre': _('Nombre')
        }

class DiaForm(forms.ModelForm):
    ejercicios = forms.ModelMultipleChoiceField(queryset=Ejercicio.objects.all())
    class Meta:
        model = Dia
        fields = ['ejercicios']
        labels = {
            'ejercicios': _('Ejercicios')
        }

视图.py

def nueva_rutina_view(request):
if request.method == "POST":
    form = RutinaForm(request.POST)
    dia_form_1 = DiaForm(request.POST)
    dia_form_2 = DiaForm(request.POST)
    dia_form_3 = DiaForm(request.POST)
    if form.is_valid() and dia_form_1.is_valid() and dia_form_2.is_valid() and dia_form_3.is_valid():
        rutina = form.save(commit=False)
        dia1 = dia_form_1.save(commit=False)
        dia2 = dia_form_2.save(commit=False)
        dia3 = dia_form_3.save(commit=False)
        rutina.save()
        dia1.rutina = rutina
        dia2.rutina = rutina
        dia3.rutina = rutina
        dia1.ejercicios = dia_form_1.ejercicios
        dia2.ejercicios = dia_form_2.ejercicios
        dia3.ejercicios = dia_form_3.ejercicios
        dia1.save()
        dia2.save()
        dia3.save()
        return redirect(historial_rutinas_view)
else:
    form = RutinaForm()
    dia_form_1 = DiaForm()
    dia_form_2 = DiaForm()
    dia_form_3 = DiaForm()        
return render(request, 'rutinas/nueva-rutina.html', {'form': form, 'dia_form_1': dia_form_1, 'dia_form_2': dia_form_2, 'dia_form_3': dia_form_3})