Viewing github.com/django/django-stable-4.1.x/docs/ref/contrib/auth.txt

```
=======================
```
```
``django.contrib.auth``
```
```
=======================
```

This document provides API reference material for the components of Django's

authentication system. For more details on the usage of these components or

how to customize authentication and authorization see the :doc:`authentication

```
topic guide </topics/auth/index>`.
```
```
.. currentmodule:: django.contrib.auth
```
```
``User`` model
```
```
==============
```
```
.. class:: models.User
```
```
Fields
```
```
------
```
```
.. class:: models.User
```
```
    :noindex:
```

    :class:`~django.contrib.auth.models.User` objects have the following

```
    fields:
```
```
    .. attribute:: username
```

        Required. 150 characters or fewer. Usernames may contain alphanumeric,

        ``_``, ``@``, ``+``, ``.`` and ``-`` characters.

        The ``max_length`` should be sufficient for many use cases. If you need

        a longer length, please use a :ref:`custom user model

        <specifying-custom-user-model>`. If you use MySQL with the ``utf8mb4``

        encoding (recommended for proper Unicode support), specify at most

        ``max_length=191`` because MySQL can only create unique indexes with

        191 characters in that case by default.

```
    .. attribute:: first_name
```

        Optional (:attr:`blank=True <django.db.models.Field.blank>`). 150

```
        characters or fewer.
```
```
    .. attribute:: last_name
```

        Optional (:attr:`blank=True <django.db.models.Field.blank>`). 150

```
        characters or fewer.
```
```
    .. attribute:: email
```

        Optional (:attr:`blank=True <django.db.models.Field.blank>`). Email

```
        address.
```
```
    .. attribute:: password
```

        Required. A hash of, and metadata about, the password. (Django doesn't

        store the raw password.) Raw passwords can be arbitrarily long and can

        contain any character. See the :doc:`password documentation

```
        </topics/auth/passwords>`.
```
```
    .. attribute:: groups
```

        Many-to-many relationship to :class:`~django.contrib.auth.models.Group`

```
    .. attribute:: user_permissions
```

        Many-to-many relationship to :class:`~django.contrib.auth.models.Permission`

```
    .. attribute:: is_staff
```

        Boolean. Designates whether this user can access the admin site.

```
    .. attribute:: is_active
```

        Boolean. Designates whether this user account should be considered

        active. We recommend that you set this flag to ``False`` instead of

        deleting accounts; that way, if your applications have any foreign keys

        to users, the foreign keys won't break.

        This doesn't necessarily control whether or not the user can log in.

        Authentication backends aren't required to check for the ``is_active``

```
        flag but the default backend
```

        (:class:`~django.contrib.auth.backends.ModelBackend`) and the

        :class:`~django.contrib.auth.backends.RemoteUserBackend` do. You can

        use :class:`~django.contrib.auth.backends.AllowAllUsersModelBackend`

        or :class:`~django.contrib.auth.backends.AllowAllUsersRemoteUserBackend`

        if you want to allow inactive users to login. In this case, you'll also

```
        want to customize the
```

        :class:`~django.contrib.auth.forms.AuthenticationForm` used by the

        :class:`~django.contrib.auth.views.LoginView` as it rejects inactive

        users. Be aware that the permission-checking methods such as

        :meth:`~django.contrib.auth.models.User.has_perm` and the

        authentication in the Django admin all return ``False`` for inactive

```
        users.
```
```
    .. attribute:: is_superuser
```

        Boolean. Designates that this user has all permissions without

```
        explicitly assigning them.
```
```
    .. attribute:: last_login
```

        A datetime of the user's last login.

```
    .. attribute:: date_joined
```

        A datetime designating when the account was created. Is set to the

        current date/time by default when the account is created.

```
Attributes
```
```
----------
```
```
.. class:: models.User
```
```
    :noindex:
```
```
    .. attribute:: is_authenticated
```

        Read-only attribute which is always ``True`` (as opposed to

        ``AnonymousUser.is_authenticated`` which is always ``False``). This is

        a way to tell if the user has been authenticated. This does not imply

        any permissions and doesn't check if the user is active or has a valid

        session. Even though normally you will check this attribute on

        ``request.user`` to find out whether it has been populated by the

        :class:`~django.contrib.auth.middleware.AuthenticationMiddleware`

        (representing the currently logged-in user), you should know this

        attribute is ``True`` for any :class:`~models.User` instance.

```
    .. attribute:: is_anonymous
```

        Read-only attribute which is always ``False``. This is a way of

        differentiating :class:`~models.User` and :class:`~models.AnonymousUser`

        objects. Generally, you should prefer using

        :attr:`~django.contrib.auth.models.User.is_authenticated` to this

```
        attribute.
```
```
Methods
```
```
-------
```
```
.. class:: models.User
```
```
    :noindex:
```
```
    .. method:: get_username()
```

        Returns the username for the user. Since the ``User`` model can be

        swapped out, you should use this method instead of referencing the

```
        username attribute directly.
```
```
    .. method:: get_full_name()
```

        Returns the :attr:`~django.contrib.auth.models.User.first_name` plus

        the :attr:`~django.contrib.auth.models.User.last_name`, with a space in

```
        between.
```
```
    .. method:: get_short_name()
```

        Returns the :attr:`~django.contrib.auth.models.User.first_name`.

    .. method:: set_password(raw_password)

        Sets the user's password to the given raw string, taking care of the

        password hashing. Doesn't save the

        :class:`~django.contrib.auth.models.User` object.

        When the ``raw_password`` is ``None``, the password will be set to an

```
        unusable password, as if
```

        :meth:`~django.contrib.auth.models.User.set_unusable_password()`

```
        were used.
```

    .. method:: check_password(raw_password)

        Returns ``True`` if the given raw string is the correct password for

        the user. (This takes care of the password hashing in making the

```
        comparison.)
```

    .. method:: set_unusable_password()

        Marks the user as having no password set.  This isn't the same as

        having a blank string for a password.

        :meth:`~django.contrib.auth.models.User.check_password()` for this user

        will never return ``True``. Doesn't save the

        :class:`~django.contrib.auth.models.User` object.

        You may need this if authentication for your application takes place

        against an existing external source such as an LDAP directory.

```
    .. method:: has_usable_password()
```
```
        Returns ``False`` if
```

        :meth:`~django.contrib.auth.models.User.set_unusable_password()` has

```
        been called for this user.
```

    .. method:: get_user_permissions(obj=None)

        Returns a set of permission strings that the user has directly.

        If ``obj`` is passed in, only returns the user permissions for this

```
        specific object.
```

    .. method:: get_group_permissions(obj=None)

        Returns a set of permission strings that the user has, through their

```
        groups.
```

        If ``obj`` is passed in, only returns the group permissions for

```
        this specific object.
```

    .. method:: get_all_permissions(obj=None)

        Returns a set of permission strings that the user has, both through

```
        group and user permissions.
```

        If ``obj`` is passed in, only returns the permissions for this

```
        specific object.
```

    .. method:: has_perm(perm, obj=None)

        Returns ``True`` if the user has the specified permission, where perm

        is in the format ``"<app label>.<permission codename>"``. (see

        documentation on :ref:`permissions <topic-authorization>`). If the user is

        inactive, this method will always return ``False``. For an active

        superuser, this method will always return ``True``.

        If ``obj`` is passed in, this method won't check for a permission for

        the model, but for this specific object.

    .. method:: has_perms(perm_list, obj=None)

        Returns ``True`` if the user has each of the specified permissions,

        where each perm is in the format

        ``"<app label>.<permission codename>"``. If the user is inactive,

        this method will always return ``False``. For an active superuser, this

        method will always return ``True``.

        If ``obj`` is passed in, this method won't check for permissions for

        the model, but for the specific object.

    .. method:: has_module_perms(package_name)

        Returns ``True`` if the user has any permissions in the given package

        (the Django app label). If the user is inactive, this method will

        always return ``False``. For an active superuser, this method will

```
        always return ``True``.
```

    .. method:: email_user(subject, message, from_email=None, **kwargs)

        Sends an email to the user. If ``from_email`` is ``None``, Django uses

        the :setting:`DEFAULT_FROM_EMAIL`. Any ``**kwargs`` are passed to the

        underlying :meth:`~django.core.mail.send_mail()` call.

```
Manager methods
```
```
---------------
```
```
.. class:: models.UserManager
```

    The :class:`~django.contrib.auth.models.User` model has a custom manager

    that has the following helper methods (in addition to the methods provided

    by :class:`~django.contrib.auth.models.BaseUserManager`):

    .. method:: create_user(username, email=None, password=None, **extra_fields)

        Creates, saves and returns a :class:`~django.contrib.auth.models.User`.

        The :attr:`~django.contrib.auth.models.User.username` and

        :attr:`~django.contrib.auth.models.User.password` are set as given. The

        domain portion of :attr:`~django.contrib.auth.models.User.email` is

        automatically converted to lowercase, and the returned

        :class:`~django.contrib.auth.models.User` object will have

        :attr:`~django.contrib.auth.models.User.is_active` set to ``True``.

```
        If no password is provided,
```

        :meth:`~django.contrib.auth.models.User.set_unusable_password()` will

```
        be called.
```

        The ``extra_fields`` keyword arguments are passed through to the

        :class:`~django.contrib.auth.models.User`’s ``__init__`` method to

        allow setting arbitrary fields on a :ref:`custom user model

```
        <auth-custom-user>`.
```

        See :ref:`Creating users <topics-auth-creating-users>` for example usage.

    .. method:: create_superuser(username, email=None, password=None, **extra_fields)

        Same as :meth:`create_user`, but sets :attr:`~models.User.is_staff` and

        :attr:`~models.User.is_superuser` to ``True``.

    .. method:: with_perm(perm, is_active=True, include_superusers=True, backend=None, obj=None)

        Returns users that have the given permission ``perm`` either in the

        ``"<app label>.<permission codename>"`` format or as a

        :class:`~django.contrib.auth.models.Permission` instance. Returns an

        empty queryset if no users who have the ``perm`` found.

        If ``is_active`` is ``True`` (default), returns only active users, or

        if ``False``, returns only inactive users. Use ``None`` to return all

        users irrespective of active state.

        If ``include_superusers`` is ``True`` (default), the result will

```
        include superusers.
```

        If ``backend`` is passed in and it's defined in

        :setting:`AUTHENTICATION_BACKENDS`, then this method will use it.

        Otherwise, it will use the ``backend`` in

        :setting:`AUTHENTICATION_BACKENDS`, if there is only one, or raise an

```
        exception.
```
```
``AnonymousUser`` object
```
```
========================
```
```
.. class:: models.AnonymousUser
```

    :class:`django.contrib.auth.models.AnonymousUser` is a class that

    implements the :class:`django.contrib.auth.models.User` interface, with

```
    these differences:
```

    * :ref:`id <automatic-primary-key-fields>` is always ``None``.

    * :attr:`~django.contrib.auth.models.User.username` is always the empty

```
      string.
```

    * :meth:`~django.contrib.auth.models.User.get_username()` always returns

```
      the empty string.
```

    * :attr:`~django.contrib.auth.models.User.is_anonymous` is ``True``

```
      instead of ``False``.
```

    * :attr:`~django.contrib.auth.models.User.is_authenticated` is

```
      ``False`` instead of ``True``.
```

    * :attr:`~django.contrib.auth.models.User.is_staff` and

      :attr:`~django.contrib.auth.models.User.is_superuser` are always

```
      ``False``.
```

    * :attr:`~django.contrib.auth.models.User.is_active` is always ``False``.

    * :attr:`~django.contrib.auth.models.User.groups` and

      :attr:`~django.contrib.auth.models.User.user_permissions` are always

```
      empty.
```

    * :meth:`~django.contrib.auth.models.User.set_password()`,

      :meth:`~django.contrib.auth.models.User.check_password()`,

      :meth:`~django.db.models.Model.save` and

      :meth:`~django.db.models.Model.delete()` raise :exc:`NotImplementedError`.

In practice, you probably won't need to use

:class:`~django.contrib.auth.models.AnonymousUser` objects on your own, but

they're used by web requests, as explained in the next section.

```
``Permission`` model
```
```
====================
```
```
.. class:: models.Permission
```
```
Fields
```
```
------
```

:class:`~django.contrib.auth.models.Permission` objects have the following

```
fields:
```
```
.. class:: models.Permission
```
```
    :noindex:
```
```
    .. attribute:: name
```

        Required. 255 characters or fewer. Example: ``'Can vote'``.

```
    .. attribute:: content_type
```

        Required. A reference to the ``django_content_type`` database table,

        which contains a record for each installed model.

```
    .. attribute:: codename
```

        Required. 100 characters or fewer. Example: ``'can_vote'``.

```
Methods
```
```
-------
```

:class:`~django.contrib.auth.models.Permission` objects have the standard

data-access methods like any other :doc:`Django model </ref/models/instances>`.

```
``Group`` model
```
```
===============
```
```
.. class:: models.Group
```
```
Fields
```
```
------
```

:class:`~django.contrib.auth.models.Group` objects have the following fields:

```
.. class:: models.Group
```
```
    :noindex:
```
```
    .. attribute:: name
```

        Required. 150 characters or fewer. Any characters are permitted.

```
        Example: ``'Awesome Users'``.
```
```
    .. attribute:: permissions
```

        Many-to-many field to :class:`~django.contrib.auth.models.Permission`::

            group.permissions.set([permission_list])

            group.permissions.add(permission, permission, ...)

            group.permissions.remove(permission, permission, ...)

```
            group.permissions.clear()
```
```
Validators
```
```
==========
```

.. class:: validators.ASCIIUsernameValidator

    A field validator allowing only ASCII letters and numbers, in addition to

    ``@``, ``.``, ``+``, ``-``, and ``_``.

.. class:: validators.UnicodeUsernameValidator

    A field validator allowing Unicode characters, in addition to ``@``, ``.``,

    ``+``, ``-``, and ``_``. The default validator for ``User.username``.

```
.. _topics-auth-signals:
```
```
Login and logout signals
```
```
========================
```

.. module:: django.contrib.auth.signals

The auth framework uses the following :doc:`signals </topics/signals>` that

can be used for notification when a user logs in or out.

```
.. data:: user_logged_in
```

    Sent when a user logs in successfully.

```
    Arguments sent with this signal:
```
```
    ``sender``
```

        The class of the user that just logged in.

```
    ``request``
```

        The current :class:`~django.http.HttpRequest` instance.

```
    ``user``
```

        The user instance that just logged in.

```
.. data:: user_logged_out
```

    Sent when the logout method is called.

```
    ``sender``
```

        As above: the class of the user that just logged out or ``None``

        if the user was not authenticated.

```
    ``request``
```

        The current :class:`~django.http.HttpRequest` instance.

```
    ``user``
```

        The user instance that just logged out or ``None`` if the

```
        user was not authenticated.
```
```
.. data:: user_login_failed
```

    Sent when the user failed to login successfully

```
    ``sender``
```

        The name of the module used for authentication.

```
    ``credentials``
```

        A dictionary of keyword arguments containing the user credentials that were

        passed to :func:`~django.contrib.auth.authenticate()` or your own custom

        authentication backend. Credentials matching a set of 'sensitive' patterns,

        (including password) will not be sent in the clear as part of the signal.

```
    ``request``
```

        The :class:`~django.http.HttpRequest` object, if one was provided to

        :func:`~django.contrib.auth.authenticate`.

```
.. _authentication-backends-reference:
```
```
Authentication backends
```
```
=======================
```

.. module:: django.contrib.auth.backends

   :synopsis: Django's built-in authentication backend classes.

This section details the authentication backends that come with Django. For

information on how to use them and how to write your own authentication

backends, see the :ref:`Other authentication sources section

<authentication-backends>` of the :doc:`User authentication guide

```
</topics/auth/index>`.
```
```
Available authentication backends
```
```
---------------------------------
```

The following backends are available in :mod:`django.contrib.auth.backends`:

```
.. class:: BaseBackend
```

    A base class that provides default implementations for all required

    methods. By default, it will reject any user and provide no permissions.

    .. method:: get_user_permissions(user_obj, obj=None)

```
        Returns an empty set.
```

    .. method:: get_group_permissions(user_obj, obj=None)

```
        Returns an empty set.
```

    .. method:: get_all_permissions(user_obj, obj=None)

        Uses :meth:`get_user_permissions` and :meth:`get_group_permissions` to

        get the set of permission strings the ``user_obj`` has.

    .. method:: has_perm(user_obj, perm, obj=None)

        Uses :meth:`get_all_permissions` to check if ``user_obj`` has the

```
        permission string ``perm``.
```
```
.. class:: ModelBackend
```

    This is the default authentication backend used by Django.  It

    authenticates using credentials consisting of a user identifier and

    password.  For Django's default user model, the user identifier is the

    username, for custom user models it is the field specified by

    USERNAME_FIELD (see :doc:`Customizing Users and authentication

```
    </topics/auth/customizing>`).
```

    It also handles the default permissions model as defined for

    :class:`~django.contrib.auth.models.User` and

    :class:`~django.contrib.auth.models.PermissionsMixin`.

    :meth:`has_perm`, :meth:`get_all_permissions`, :meth:`get_user_permissions`,

    and :meth:`get_group_permissions` allow an object to be passed as a

    parameter for object-specific permissions, but this backend does not

    implement them other than returning an empty set of permissions if

```
    ``obj is not None``.
```

    :meth:`with_perm` also allows an object to be passed as a parameter, but

    unlike others methods it returns an empty queryset if ``obj is not None``.

    .. method:: authenticate(request, username=None, password=None, **kwargs)

        Tries to authenticate ``username`` with ``password`` by calling

```
        :meth:`User.check_password
```

        <django.contrib.auth.models.User.check_password>`. If no ``username``

        is provided, it tries to fetch a username from ``kwargs`` using the

        key :attr:`CustomUser.USERNAME_FIELD

        <django.contrib.auth.models.CustomUser.USERNAME_FIELD>`. Returns an

        authenticated user or ``None``.

        ``request`` is an :class:`~django.http.HttpRequest` and may be ``None``

        if it wasn't provided to :func:`~django.contrib.auth.authenticate`

        (which passes it on to the backend).

    .. method:: get_user_permissions(user_obj, obj=None)

        Returns the set of permission strings the ``user_obj`` has from their

        own user permissions. Returns an empty set if

        :attr:`~django.contrib.auth.models.AbstractBaseUser.is_anonymous` or

        :attr:`~django.contrib.auth.models.CustomUser.is_active` is ``False``.

    .. method:: get_group_permissions(user_obj, obj=None)

        Returns the set of permission strings the ``user_obj`` has from the

        permissions of the groups they belong. Returns an empty set if

        :attr:`~django.contrib.auth.models.AbstractBaseUser.is_anonymous` or

        :attr:`~django.contrib.auth.models.CustomUser.is_active`  is ``False``.

    .. method:: get_all_permissions(user_obj, obj=None)

        Returns the set of permission strings the ``user_obj`` has, including both

        user permissions and group permissions. Returns an empty set if

        :attr:`~django.contrib.auth.models.AbstractBaseUser.is_anonymous` or

        :attr:`~django.contrib.auth.models.CustomUser.is_active` is ``False``.

    .. method:: has_perm(user_obj, perm, obj=None)

        Uses :meth:`get_all_permissions` to check if ``user_obj`` has the

        permission string ``perm``. Returns ``False`` if the user is not

        :attr:`~django.contrib.auth.models.CustomUser.is_active`.

    .. method:: has_module_perms(user_obj, app_label)

        Returns whether the ``user_obj`` has any permissions on the app

```
        ``app_label``.
```

    .. method:: user_can_authenticate()

        Returns whether the user is allowed to authenticate. To match the

        behavior of :class:`~django.contrib.auth.forms.AuthenticationForm`

        which :meth:`prohibits inactive users from logging in

        <django.contrib.auth.forms.AuthenticationForm.confirm_login_allowed>`,

        this method returns ``False`` for users with :attr:`is_active=False

        <django.contrib.auth.models.User.is_active>`. Custom user models that

        don't have an :attr:`~django.contrib.auth.models.CustomUser.is_active`

```
        field are allowed.
```

    .. method:: with_perm(perm, is_active=True, include_superusers=True, obj=None)

        Returns all active users who have the permission ``perm`` either in

        the form of ``"<app label>.<permission codename>"`` or a

        :class:`~django.contrib.auth.models.Permission` instance. Returns an

        empty queryset if no users who have the ``perm`` found.

        If ``is_active`` is ``True`` (default), returns only active users, or

        if ``False``, returns only inactive users. Use ``None`` to return all

        users irrespective of active state.

        If ``include_superusers`` is ``True`` (default), the result will

```
        include superusers.
```
```
.. class:: AllowAllUsersModelBackend
```

    Same as :class:`ModelBackend` except that it doesn't reject inactive users

    because :meth:`~ModelBackend.user_can_authenticate` always returns ``True``.

    When using this backend, you'll likely want to customize the

    :class:`~django.contrib.auth.forms.AuthenticationForm` used by the

    :class:`~django.contrib.auth.views.LoginView` by overriding the

    :meth:`~django.contrib.auth.forms.AuthenticationForm.confirm_login_allowed`

    method as it rejects inactive users.

```
.. class:: RemoteUserBackend
```

    Use this backend to take advantage of external-to-Django-handled

    authentication.  It authenticates using usernames passed in

    :attr:`request.META['REMOTE_USER'] <django.http.HttpRequest.META>`.  See

    the :doc:`Authenticating against REMOTE_USER </howto/auth-remote-user>`

```
    documentation.
```

    If you need more control, you can create your own authentication backend

    that inherits from this class and override these attributes or methods:

```
    .. attribute:: create_unknown_user
```

        ``True`` or ``False``. Determines whether or not a user object is

        created if not already in the database  Defaults to ``True``.

    .. method:: authenticate(request, remote_user)

        The username passed as ``remote_user`` is considered trusted. This

        method returns the user object with the given username, creating a new

        user object if :attr:`~RemoteUserBackend.create_unknown_user` is

```
        ``True``.
```

        Returns ``None`` if :attr:`~RemoteUserBackend.create_unknown_user` is

        ``False`` and a ``User`` object with the given username is not found in

```
        the database.
```

        ``request`` is an :class:`~django.http.HttpRequest` and may be ``None``

        if it wasn't provided to :func:`~django.contrib.auth.authenticate`

        (which passes it on to the backend).

    .. method:: clean_username(username)

        Performs any cleaning on the ``username`` (e.g. stripping LDAP DN

        information) prior to using it to get or create a user object. Returns

```
        the cleaned username.
```

    .. method:: configure_user(request, user, created=True)

        Configures the user on each authentication attempt. This method is

        called immediately after fetching or creating the user being

        authenticated, and can be used to perform custom setup actions, such as

        setting the user's groups based on attributes in an LDAP directory.

```
        Returns the user object.
```

        The setup can be performed either once when the user is created

        (``created`` is ``True``) or on existing users (``created`` is

        ``False``) as a way of synchronizing attributes between the remote and

```
        the local systems.
```

        ``request`` is an :class:`~django.http.HttpRequest` and may be ``None``

        if it wasn't provided to :func:`~django.contrib.auth.authenticate`

        (which passes it on to the backend).

```
        .. versionchanged:: 4.1
```

            The ``created`` argument was added.

    .. method:: user_can_authenticate()

        Returns whether the user is allowed to authenticate. This method

        returns ``False`` for users with :attr:`is_active=False

        <django.contrib.auth.models.User.is_active>`. Custom user models that

        don't have an :attr:`~django.contrib.auth.models.CustomUser.is_active`

```
        field are allowed.
```

.. class:: AllowAllUsersRemoteUserBackend

    Same as :class:`RemoteUserBackend` except that it doesn't reject inactive

    users because :attr:`~RemoteUserBackend.user_can_authenticate` always

```
    returns ``True``.
```
```
Utility functions
```
```
=================
```
```
.. currentmodule:: django.contrib.auth
```
```
.. function:: get_user(request)
```

    Returns the user model instance associated with the given ``request``’s

```
    session.
```

    It checks if the authentication backend stored in the session is present in

    :setting:`AUTHENTICATION_BACKENDS`. If so, it uses the backend's

    ``get_user()`` method to retrieve the user model instance and then verifies

    the session by calling the user model's

    :meth:`~django.contrib.auth.models.AbstractBaseUser.get_session_auth_hash`

    method. If the verification fails and :setting:`SECRET_KEY_FALLBACKS` are

    provided, it verifies the session against each fallback key using

    :meth:`~django.contrib.auth.models.AbstractBaseUser.\

```
    get_session_auth_fallback_hash`.
```

    Returns an instance of :class:`~django.contrib.auth.models.AnonymousUser`

    if the authentication backend stored in the session is no longer in

    :setting:`AUTHENTICATION_BACKENDS`, if a user isn't returned by the

    backend's ``get_user()`` method, or if the session auth hash doesn't

```
    validate.
```
```
    .. versionchanged:: 4.1.8
```

        Fallback verification with :setting:`SECRET_KEY_FALLBACKS` was added.