Issue with Tutorial pt 5 "Fixing the bug"

[John Wall]

Hello all,

I am working through the Django tutorial. I've made it to "Fixing the bug" within part 5, but am having issues. The tutorial shows the following lines:

def was_published_recently(self):
    now = timezone.now()
    return now - datetime.timedelta(days=1) <= self.pub_date <= now

to be placed in polls/models.py.

I have made these changes and re-run the test:

$ python manage.py test polls

 Which throws:

Creating test database for alias 'default'...

SystemCheckError: System check identified some issues:

ERRORS:

<class 'polls.admin.QuestionAdmin'>: (admin.E108) The value of 'list_display[2]' refers to 'was_published_recently', which is not a callable, an attribute of 'QuestionAdmin', or an attribute or method on 'polls.Question'.

System check identified 1 issue (0 silenced).

I have gone into admin.py, but have been unable to spot the error. My admin.py looks like:

from django.contrib import admin

from .models import Question, Choice

class ChoiceInline(admin.TabularInline):

    model = Choice

    extra = 3

class QuestionAdmin(admin.ModelAdmin):

    fieldsets = [

        (None,               {'fields': ['question_text']}),

        ('Date information', {'fields': ['pub_date'], 'classes': ['collapse']}),

    ]

    inlines = [ChoiceInline]

class QuestionAdmin(admin.ModelAdmin):

list_display = ('question_text', 'pub_date', 'was_published_recently')

list_filter = ['pub_date']

search_fields = ['question_text']

admin.site.register(Question, QuestionAdmin)

admin.site.register(Choice)

Does anyone have any recommendations as to what my issue might be?

Thanks,

John

[Melvyn Sopacua]

On Monday 23 January 2017 08:22:28 John Wall wrote:

 

>

> class QuestionAdmin(admin.ModelAdmin):

> fieldsets = [

 

and whoops:

> class QuestionAdmin(admin.ModelAdmin):

 

You have 2, sir.

--

Melvyn Sopacua

[John Wall]

I'm guessing you mean that I have to class calls for QuestionAdmin? I was not able to get the code from the tutorial to work any other way. Might it be some issue with my version of Python?

[Tim Graham]

Correct, you shouldn't declare class QuestionAdmin(...) twice. What problem do you see if you combine those classes? It's unlikely related to your Python version.

[Melvyn Sopacua]

On Tuesday 24 January 2017 11:14:58 Tim Graham wrote:

> Correct, you shouldn't declare class QuestionAdmin(...) twice. What

> problem do you see if you combine those classes? It's unlikely

> related to your Python version.

>

> On Tuesday, January 24, 2017 at 10:45:50 AM UTC-5, John Wall wrote:

> > I'm guessing you mean that I have to class calls for QuestionAdmin?

 

Note that Tim calls it "declare" and you call it "calls". Not being pedantic, but it's the key to understanding your mistake: You can only declare something once in the same scope. You can call it as many times as you want.

 

The scope is also important:

 

class Awesome(models.Model):

name = models.CharField(max_length=200)

 

def awesome_factory(unique=False):

class Awesome(models.Model):

name = models.CharField(max_length=200, unique=unique)

class Meta:

abstract = True

return Awesome

 

class TheBomb(awesome_factory(unique=True)):

pass

 

class Magnificent(awesome_factory()):

pass

 

As you see, I declared two Awesome classes, but the second is in the scope of the awesome_factory function - so this works.

 

The result is that in the outer scope Awesome and Magnificent are identical models with a different name and that TheBomb has a name field that enforces uniqueness.

 

Hope this sheds some light on things :)

--

Melvyn Sopacua