'SlotInline' object has no attribute 'queryset'

[satish-gathole-driveu]

I am using Django 1.8.1

Models:

class Profile(models.Model): charge_by = models.CharField(max_length=16, choices=CHARGE_BY_CHOICES, blank=False, null=False) valid_from = models.DateTimeField(blank=True, null=True) valid_to = models.DateTimeField(blank=True, null=True)

class Slot(models.Model): profile = models.ForeignKey(Profile) start_time = models.TimeField() end_time = models.TimeField()

class SlotSlab(models.Model): slot = models.ForeignKey(Slot) num_hours = models.SmallIntegerField(blank=False, null=False) price = models.DecimalField(max_digits=10, decimal_places=2)

And in admin.py I have following

class SlotSlabline(NestedTabularInline): model = SlotSlab

class SlotInline(NestedTabularInline): model = Slot inlines = [SlotSlabline,]

class ProfileAdmin(NestedModelAdmin): inlines = [SlotInline,]

admin.site.register(Profile, ProfileAdmin)

But When I tried to create Profile getting error(Attached image):

'SlotInline' object has no attribute 'queryset'