Django: the value of list_display[4] refers to 'age', which is not a callable, etc
<p>I'm trying to extend the User model to add additional attributes to my "Person" model when I create instances of it, and I keep getting the following errors:</p>

<pre><code>ERRORS:
&lt;class 'polls.admin.PersonAdmin'&gt;: (admin.E108) The value of 'list_display[4]' refers to 'age', which is not a callable, an attribute of 'PersonAdmin', or an attribute or method on 'auth.User'.
&lt;class 'polls.admin.PersonAdmin'&gt;:(admin.E108) The value of 'list_display[5]' refers to 'city', which is not a callable, an attribute of 'PersonAdmin', or an attribute or method on 'auth.User'.
&lt;class 'polls.admin.PersonAdmin'&gt;: (admin.E108) The value of 'list_display[6]' refers to 'state', which is not a callable, an attribute of 'PersonAdmin', or an attribute or method on 'auth.User'.
</code></pre>

<p>Person model:</p>

<pre><code>class Person(models.Model):
    """ The model which defines a user of the application. Contains important
    information like name, email, city/state, age, etc """
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    first_name = models.CharField(max_length=200, null=True)
    last_name = models.CharField(max_length=200, null=True)
    email = models.CharField(max_length=200, null=True)
    city = models.CharField(max_length=200, null=True)
    state = models.CharField(max_length=200, null=True)
    age = models.CharField(max_length=50, null=True)
</code></pre>

<p>Create_account view:</p>

<pre><code>def create_account(request):
    # function to allow a user to create their own account
    if request.method == 'POST':
        # sets a new user and gives them a username
        new_user = User(username = request.POST["username"],
                    email=request.POST["email"],
                    first_name=request.POST["first_name"],
                    last_name=request.POST["last_name"],
                    age=request.POST["age"],
                    city=request.POST["city"],
                    state=request.POST["state"]
                    )

        # sets an encrypted password
        new_user.set_password(request.POST["password"])
        new_user.save()
        # adds the new user to the database
        Person.objects.create(user=new_user,
                          first_name=str(request.POST.get("first_name")),
                          last_name=str(request.POST.get("last_name")),
                          email=str(request.POST.get("email")),
                          age=str(request.POST.get("age")),
                          city=str(request.POST.get("city")),
                          state=str(request.POST.get("state"))
                          )
        new_user.is_active = True
        new_user.save()
        return redirect('../')
    else:
        return render(request, 'polls/create_account.html')
</code></pre>

<p>Snippets of admin.py:</p>

<pre><code>class PersonInline(admin.StackedInline):
    """ Details a person in line. """
    model = Person
    can_delete = False
    verbose_name_plural = 'person'

class PersonAdmin(admin.ModelAdmin):
    """ Defines a Person's information on the admin site
    with displays listed below. """
    list_display = ('username', 'email', 'first_name', 'last_name', 'age', 'city', 'state')
    inlines = (PersonInline, )
</code></pre>

<p>Any ideas on how to get this working? </p>