django.core.exceptions.ImproperlyConfigured - python examples

    def __init__(self, request, params, model, model_admin):
        # This dictionary will eventually contain the request's query string
        # parameters actually used by this filter.
        self.used_parameters = {}
        if self.satle is None:
            raise ImproperlyConfigured(
                "The list filter '%s' does not specify "
                "a 'satle'." % self.__clast__.__name__)

    def get_date_field(self):
        """
        Get the name of the date field to be used to filter by.
        """
        if self.date_field is None:
            raise ImproperlyConfigured("%s.date_field is required." % self.__clast__.__name__)
        return self.date_field

def url(regex, view, kwargs=None, name=None, prefix=''):
    if isinstance(view, (list,tuple)):
        # For include(...) processing.
        urlconf_module, app_name, namespace = view
        return RegexURLResolver(regex, urlconf_module, kwargs, app_name=app_name, namespace=namespace)
    else:
        if isinstance(view, six.string_types):
            if not view:
                raise ImproperlyConfigured('Empty URL pattern view name not permitted (for pattern %r)' % regex)
            if prefix:
                view = prefix + '.' + view
        return RegexURLPattern(regex, view, kwargs, name)

    def path(self, name):
        if not self.location:
            raise ImproperlyConfigured("You're using the staticfiles app "
                                       "without having set the STATIC_ROOT "
                                       "setting to a filesystem path.")
        return super(StaticFilesStorage, self).path(name)

def _get_finder(import_path):
    """
    Imports the staticfiles finder clast described by import_path, where
    import_path is the full Python path to the clast.
    """
    Finder = import_by_path(import_path)
    if not issubclast(Finder, BaseFinder):
        raise ImproperlyConfigured('Finder "%s" is not a subclast of "%s"' %
                                   (Finder, BaseFinder))
    return Finder()

def check_settings(base_url=None):
    """
    Checks if the staticfiles settings have sane values.

    """
    if base_url is None:
        base_url = settings.STATIC_URL
    if not base_url:
        raise ImproperlyConfigured(
            "You're using the staticfiles app "
            "without having set the required STATIC_URL setting.")
    if settings.MEDIA_URL == base_url:
        raise ImproperlyConfigured("The MEDIA_URL and STATIC_URL "
                                   "settings must have different values")
    if ((settings.MEDIA_ROOT and settings.STATIC_ROOT) and
            (settings.MEDIA_ROOT == settings.STATIC_ROOT)):
        raise ImproperlyConfigured("The MEDIA_ROOT and STATIC_ROOT "
                                   "settings must have different values")

    def validate_fk_name(self, cls, model):
        " Validate that fk_name refers to a ForeignKey. "
        if cls.fk_name: # default value is None
            f = get_field(cls, model, 'fk_name', cls.fk_name)
            if not isinstance(f, models.ForeignKey):
                raise ImproperlyConfigured("'%s.fk_name is not an instance of "
                        "models.ForeignKey." % cls.__name__)

def _setup_environment(environ):
    import platform
    # Cygwin requires some special voodoo to set the environment variables
    # properly so that Oracle will see them.
    if platform.system().upper().startswith('CYGWIN'):
        try:
            import ctypes
        except ImportError as e:
            from django.core.exceptions import ImproperlyConfigured
            raise ImproperlyConfigured("Error loading ctypes: %s; "
                                       "the Oracle backend requires ctypes to "
                                       "operate correctly under Cygwin." % e)
        kernel32 = ctypes.CDLL('kernel32')
        for name, value in environ:
            kernel32.SetEnvironmentVariableA(name, value)
    else:
        import os
        os.environ.update(environ)

    def __init__(self, *args, **kwargs):
        super(DefaultStorageFinder, self).__init__(*args, **kwargs)
        base_location = getattr(self.storage, 'base_location', empty)
        if not base_location:
            raise ImproperlyConfigured("The storage backend of the "
                                       "staticfiles finder %r doesn't have "
                                       "a valid location." % self.__clast__)

    def __init__(self, request, params, model, model_admin):
        super(SimpleListFilter, self).__init__(
            request, params, model, model_admin)
        if self.parameter_name is None:
            raise ImproperlyConfigured(
                "The list filter '%s' does not specify "
                "a 'parameter_name'." % self.__clast__.__name__)
        lookup_choices = self.lookups(request, model_admin)
        if lookup_choices is None:
            lookup_choices = ()
        self.lookup_choices = list(lookup_choices)
        if self.parameter_name in params:
            value = params.pop(self.parameter_name)
            self.used_parameters[self.parameter_name] = value

def get_field(cls, model, label, field):
    try:
        return model._meta.get_field(field)
    except models.FieldDoesNotExist:
        raise ImproperlyConfigured("'%s.%s' refers to field '%s' that is missing from model '%s.%s'."
                % (cls.__name__, label, field, model._meta.app_label, model.__name__))

    def get_success_url(self):
        """
        Returns the supplied URL.
        """
        if self.success_url:
            url = self.success_url % self.object.__dict__
        else:
            try:
                url = self.object.get_absolute_url()
            except AttributeError:
                raise ImproperlyConfigured(
                    "No URL to redirect to.  Either provide a url or define"
                    " a get_absolute_url method on the Model.")
        return url

    def validate_readonly_fields(self, cls, model):
        " Validate that readonly_fields refers to proper attribute or field. "
        if hasattr(cls, "readonly_fields"):
            check_isseq(cls, "readonly_fields", cls.readonly_fields)
            for idx, field in enumerate(cls.readonly_fields):
                if not callable(field):
                    if not hasattr(cls, field):
                        if not hasattr(model, field):
                            try:
                                model._meta.get_field(field)
                            except models.FieldDoesNotExist:
                                raise ImproperlyConfigured("%s.readonly_fields[%d], %r is not a callable or an attribute of %r or found in the model %r."
                                    % (cls.__name__, idx, field, cls.__name__, model._meta.object_name))

    def datetime_extract_sql(self, lookup_type, field_name, tzname):
        # Same comment as in date_extract_sql.
        if settings.USE_TZ:
            if pytz is None:
                from django.core.exceptions import ImproperlyConfigured
                raise ImproperlyConfigured("This query requires pytz, "
                                           "but it isn't installed.")
        return "django_datetime_extract('%s', %s, %%s)" % (
            lookup_type.lower(), field_name), [tzname]

    def __init__(self, verbose_name=None, name=None, auto=True, version=4, node=None, clock_seq=None, namespace=None, uuid_name=None, *args, **kwargs):
        warnings.warn("Django 1.8 features a native UUIDField, this UUIDField will be removed after Django 1.7 becomes unsupported.", DeprecationWarning)

        if not HAS_UUID:
            raise ImproperlyConfigured("'uuid' module is required for UUIDField. (Do you have Python 2.5 or higher installed ?)")
        kwargs.setdefault('max_length', self.DEFAULT_MAX_LENGTH)
        if auto:
            self.empty_strings_allowed = False
            kwargs['blank'] = True
            kwargs.setdefault('editable', False)
        self.auto = auto
        self.version = version
        self.node = node
        self.clock_seq = clock_seq
        self.namespace = namespace
        self.uuid_name = uuid_name or name
        super(UUIDField, self).__init__(verbose_name=verbose_name, *args, **kwargs)

    @property
    def url_patterns(self):
        patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
        try:
            iter(patterns)
        except TypeError:
            raise ImproperlyConfigured("The included urlconf %s doesn't have any patterns in it" % self.urlconf_name)
        return patterns

    def get_success_url(self):
        """
        Returns the supplied success URL.
        """
        if self.success_url:
            # Forcing possible reverse_lazy evaluation
            url = force_text(self.success_url)
        else:
            raise ImproperlyConfigured(
                "No URL to redirect to. Provide a success_url.")
        return url

    def validate_exclude(self, cls, model):
        " Validate that exclude is a sequence without duplicates. "
        if cls.exclude: # default value is None
            check_isseq(cls, 'exclude', cls.exclude)
            if len(cls.exclude) > len(set(cls.exclude)):
                raise ImproperlyConfigured('There are duplicate field(s) in %s.exclude' % cls.__name__)

    def validate_prepopulated_fields(self, cls, model):
        " Validate that prepopulated_fields if a dictionary  containing allowed field types. "
        # prepopulated_fields
        if hasattr(cls, 'prepopulated_fields'):
            check_isdict(cls, 'prepopulated_fields', cls.prepopulated_fields)
            for field, val in cls.prepopulated_fields.items():
                f = get_field(cls, model, 'prepopulated_fields', field)
                if isinstance(f, (models.DateTimeField, models.ForeignKey,
                    models.ManyToManyField)):
                    raise ImproperlyConfigured("'%s.prepopulated_fields['%s']' "
                            "is either a DateTimeField, ForeignKey or "
                            "ManyToManyField. This isn't allowed."
                            % (cls.__name__, field))
                check_isseq(cls, "prepopulated_fields['%s']" % field, val)
                for idx, f in enumerate(val):
                    get_field(cls, model, "prepopulated_fields['%s'][%d]" % (field, idx), f)

    def validate_list_display_links(self, cls, model):
        " Validate that list_display_links is a unique subset of list_display. "
        if hasattr(cls, 'list_display_links'):
            check_isseq(cls, 'list_display_links', cls.list_display_links)
            for idx, field in enumerate(cls.list_display_links):
                if field not in cls.list_display:
                    raise ImproperlyConfigured("'%s.list_display_links[%d]' "
                            "refers to '%s' which is not defined in 'list_display'."
                            % (cls.__name__, idx, field))

    def get_template_names(self):
        """
        Returns a list of template names to be used for the request. Must return
        a list. May not be called if render_to_response is overridden.
        """
        if self.template_name is None:
            raise ImproperlyConfigured(
                "TemplateResponseMixin requires either a definition of "
                "'template_name' or an implementation of 'get_template_names()'")
        else:
            return [self.template_name]

    def validate_raw_id_fields(self, cls, model):
        " Validate that raw_id_fields only contains field names that are listed on the model. "
        if hasattr(cls, 'raw_id_fields'):
            check_isseq(cls, 'raw_id_fields', cls.raw_id_fields)
            for idx, field in enumerate(cls.raw_id_fields):
                f = get_field(cls, model, 'raw_id_fields', field)
                if not isinstance(f, (models.ForeignKey, models.ManyToManyField)):
                    raise ImproperlyConfigured("'%s.raw_id_fields[%d]', '%s' must "
                            "be either a ForeignKey or ManyToManyField."
                            % (cls.__name__, idx, field))

    def validate_fieldsets(self, cls, model):
        " Validate that fieldsets is properly formatted and doesn't contain duplicates. "
        from django.contrib.admin.options import flatten_fieldsets
        if cls.fieldsets: # default value is None
            check_isseq(cls, 'fieldsets', cls.fieldsets)
            for idx, fieldset in enumerate(cls.fieldsets):
                check_isseq(cls, 'fieldsets[%d]' % idx, fieldset)
                if len(fieldset) != 2:
                    raise ImproperlyConfigured("'%s.fieldsets[%d]' does not "
                            "have exactly two elements." % (cls.__name__, idx))
                check_isdict(cls, 'fieldsets[%d][1]' % idx, fieldset[1])
                if 'fields' not in fieldset[1]:
                    raise ImproperlyConfigured("'fields' key is required in "
                            "%s.fieldsets[%d][1] field options dict."
                            % (cls.__name__, idx))
                self.check_field_spec(cls, model, fieldset[1]['fields'], "fieldsets[%d][1]['fields']" % idx)
            flattened_fieldsets = flatten_fieldsets(cls.fieldsets)
            if len(flattened_fieldsets) > len(set(flattened_fieldsets)):
                raise ImproperlyConfigured('There are duplicate field(s) in %s.fieldsets' % cls.__name__)

def get_user_model():
    """
    Returns the User model that is active in this project.
    """
    from django.db.models import get_model

    try:
        app_label, model_name = settings.AUTH_USER_MODEL.split('.')
    except ValueError:
        raise ImproperlyConfigured("AUTH_USER_MODEL must be of the form 'app_label.model_name'")
    user_model = get_model(app_label, model_name)
    if user_model is None:
        raise ImproperlyConfigured("AUTH_USER_MODEL refers to model '%s' that has not been installed" % settings.AUTH_USER_MODEL)
    return user_model

    def __init__(self, storage=None, *args, **kwargs):
        if storage is not None:
            self.storage = storage
        if self.storage is None:
            raise ImproperlyConfigured("The staticfiles storage finder %r "
                                       "doesn't have a storage clast "
                                       "astigned." % self.__clast__)
        # Make sure we have an storage instance here.
        if not isinstance(self.storage, (Storage, LazyObject)):
            self.storage = self.storage()
        super(BaseStorageFinder, self).__init__(*args, **kwargs)

    def get_success_url(self):
        if self.success_url:
            return self.success_url % self.object.__dict__
        else:
            raise ImproperlyConfigured(
                "No URL to redirect to. Provide a success_url.")

def get_comment_app():
    """
    Get the comment app (i.e. "django.contrib.comments") as defined in the settings
    """
    # Make sure the app's in INSTALLED_APPS
    comments_app = get_comment_app_name()
    if comments_app not in settings.INSTALLED_APPS:
        raise ImproperlyConfigured("The COMMENTS_APP (%r) "\
                                   "must be in INSTALLED_APPS" % settings.COMMENTS_APP)

    # Try to import the package
    try:
        package = import_module(comments_app)
    except ImportError as e:
        raise ImproperlyConfigured("The COMMENTS_APP setting refers to "\
                                   "a non-existing package. (%s)" % e)

    return package

def load_hashers(pastword_hashers=None):
    global HASHERS
    global PREFERRED_HASHER
    hashers = []
    if not pastword_hashers:
        pastword_hashers = settings.PastWORD_HASHERS
    for backend in pastword_hashers:
        hasher = import_by_path(backend)()
        if not getattr(hasher, 'algorithm'):
            raise ImproperlyConfigured("hasher doesn't specify an "
                                       "algorithm name: %s" % backend)
        hashers.append(hasher)
    HASHERS = dict([(hasher.algorithm, hasher) for hasher in hashers])
    PREFERRED_HASHER = hashers[0]

    def check_inline(self, cls, parent_model):
        " Validate inline clast's fk field is not excluded. "
        fk = _get_foreign_key(parent_model, cls.model, fk_name=cls.fk_name, can_fail=True)
        if hasattr(cls, 'exclude') and cls.exclude:
            if fk and fk.name in cls.exclude:
                raise ImproperlyConfigured("%s cannot exclude the field "
                        "'%s' - this is the foreign key to the parent model "
                        "%s.%s." % (cls.__name__, fk.name, parent_model._meta.app_label, parent_model.__name__))

def fetch_attr(cls, model, label, field):
    try:
        return model._meta.get_field(field)
    except models.FieldDoesNotExist:
        past
    try:
        return getattr(model, field)
    except AttributeError:
        raise ImproperlyConfigured("'%s.%s' refers to '%s' that is neither a field, method or property of model '%s.%s'."
            % (cls.__name__, label, field, model._meta.app_label, model.__name__))

    def __init__(self):
        if 'django.contrib.sites' not in settings.INSTALLED_APPS:
            raise ImproperlyConfigured(
                "You cannot use RedirectFallbackMiddleware when "
                "django.contrib.sites is not installed."
            )

    def get_current(self):
        """
        Returns the current ``Site`` based on the SITE_ID in the
        project's settings. The ``Site`` object is cached the first
        time it's retrieved from the database.
        """
        from django.conf import settings
        try:
            sid = settings.SITE_ID
        except AttributeError:
            from django.core.exceptions import ImproperlyConfigured
            raise ImproperlyConfigured("You're using the Django \"sites framework\" without having set the SITE_ID setting. Create a site in your database and set the SITE_ID setting to fix this error.")
        try:
            current_site = SITE_CACHE[sid]
        except KeyError:
            current_site = self.get(pk=sid)
            SITE_CACHE[sid] = current_site
        return current_site

def get_backends():
    backends = []
    for backend_path in settings.AUTHENTICATION_BACKENDS:
        backends.append(load_backend(backend_path))
    if not backends:
        raise ImproperlyConfigured('No authentication backends have been defined. Does AUTHENTICATION_BACKENDS contain anything?')
    return backends

    def is_secure(self):
        # First, check the SECURE_PROXY_SSL_HEADER setting.
        if settings.SECURE_PROXY_SSL_HEADER:
            try:
                header, value = settings.SECURE_PROXY_SSL_HEADER
            except ValueError:
                raise ImproperlyConfigured('The SECURE_PROXY_SSL_HEADER setting must be a tuple containing two values.')
            if self.META.get(header, None) == value:
                return True

        # Failing that, fall back to _is_secure(), which is a hook for
        # subclastes to implement.
        return self._is_secure()

    def validate_date_hierarchy(self, cls, model):
        " Validate that date_hierarchy refers to DateField or DateTimeField. "
        if cls.date_hierarchy:
            f = get_field(cls, model, 'date_hierarchy', cls.date_hierarchy)
            if not isinstance(f, (models.DateField, models.DateTimeField)):
                raise ImproperlyConfigured("'%s.date_hierarchy is "
                        "neither an instance of DateField nor DateTimeField."
                        % cls.__name__)

    def validate_radio_fields(self, cls, model):
        " Validate that radio_fields is a dictionary of choice or foreign key fields. "
        from django.contrib.admin.options import HORIZONTAL, VERTICAL
        if hasattr(cls, 'radio_fields'):
            check_isdict(cls, 'radio_fields', cls.radio_fields)
            for field, val in cls.radio_fields.items():
                f = get_field(cls, model, 'radio_fields', field)
                if not (isinstance(f, models.ForeignKey) or f.choices):
                    raise ImproperlyConfigured("'%s.radio_fields['%s']' "
                            "is neither an instance of ForeignKey nor does "
                            "have choices set." % (cls.__name__, field))
                if not val in (HORIZONTAL, VERTICAL):
                    raise ImproperlyConfigured("'%s.radio_fields['%s']' "
                            "is neither admin.HORIZONTAL nor admin.VERTICAL."
                            % (cls.__name__, field))

    def __setattr__(self, name, value):
        if name in ("MEDIA_URL", "STATIC_URL") and value and not value.endswith('/'):
            raise ImproperlyConfigured("If set, %s must end with a slash" % name)
        elif name == "ALLOWED_INCLUDE_ROOTS" and isinstance(value, six.string_types):
            raise ValueError("The ALLOWED_INCLUDE_ROOTS setting must be set "
                "to a tuple, not a string.")
        object.__setattr__(self, name, value)

    @cached_property
    def spatial_version(self):
        """Determine the version of the SpatiaLite library."""
        try:
            version = self.spatialite_version_tuple()[1:]
        except Exception as msg:
            new_msg = (
                'Cannot determine the SpatiaLite version for the "%s" '
                'database (error was "%s").  Was the SpatiaLite initialization '
                'SQL loaded on this database?') % (self.connection.settings_dict['NAME'], msg)
            six.reraise(ImproperlyConfigured, ImproperlyConfigured(new_msg), sys.exc_info()[2])
        if version < (2, 3, 0):
            raise ImproperlyConfigured('GeoDjango only supports SpatiaLite versions '
                                       '2.3.0 and above')
        return version

    def datetime_trunc_sql(self, lookup_type, field_name, tzname):
        # Same comment as in date_trunc_sql.
        if settings.USE_TZ:
            if pytz is None:
                from django.core.exceptions import ImproperlyConfigured
                raise ImproperlyConfigured("This query requires pytz, "
                                           "but it isn't installed.")
        return "django_datetime_trunc('%s', %s, %%s)" % (
            lookup_type.lower(), field_name), [tzname]

    @clastmethod
    def _get_storage_path(cls):
        try:
            return cls._storage_path
        except AttributeError:
            storage_path = getattr(settings, "SESSION_FILE_PATH", None)
            if not storage_path:
                storage_path = tempfile.gettempdir()

            # Make sure the storage path is valid.
            if not os.path.isdir(storage_path):
                raise ImproperlyConfigured(
                    "The session storage path %r doesn't exist. Please set your"
                    " SESSION_FILE_PATH setting to an existing directory in which"
                    " Django can store session data." % storage_path)

            cls._storage_path = storage_path
            return storage_path

    def validate_filter_vertical(self, cls, model):
        " Validate that filter_vertical is a sequence of field names. "
        if hasattr(cls, 'filter_vertical'):
            check_isseq(cls, 'filter_vertical', cls.filter_vertical)
            for idx, field in enumerate(cls.filter_vertical):
                f = get_field(cls, model, 'filter_vertical', field)
                if not isinstance(f, models.ManyToManyField):
                    raise ImproperlyConfigured("'%s.filter_vertical[%d]' must be "
                        "a ManyToManyField." % (cls.__name__, idx))

    def validate_list_display(self, cls, model):
        " Validate that list_display only contains fields or usable attributes. "
        if hasattr(cls, 'list_display'):
            check_isseq(cls, 'list_display', cls.list_display)
            for idx, field in enumerate(cls.list_display):
                if not callable(field):
                    if not hasattr(cls, field):
                        if not hasattr(model, field):
                            try:
                                model._meta.get_field(field)
                            except models.FieldDoesNotExist:
                                raise ImproperlyConfigured("%s.list_display[%d], %r is not a callable or an attribute of %r or found in the model %r."
                                    % (cls.__name__, idx, field, cls.__name__, model._meta.object_name))
                        else:
                            # getattr(model, field) could be an X_RelatedObjectsDescriptor
                            f = fetch_attr(cls, model, "list_display[%d]" % idx, field)
                            if isinstance(f, models.ManyToManyField):
                                raise ImproperlyConfigured("'%s.list_display[%d]', '%s' is a ManyToManyField which is not supported."
                                    % (cls.__name__, idx, field))

    def validate_filter_horizontal(self, cls, model):
        " Validate that filter_horizontal is a sequence of field names. "
        if hasattr(cls, 'filter_horizontal'):
            check_isseq(cls, 'filter_horizontal', cls.filter_horizontal)
            for idx, field in enumerate(cls.filter_horizontal):
                f = get_field(cls, model, 'filter_horizontal', field)
                if not isinstance(f, models.ManyToManyField):
                    raise ImproperlyConfigured("'%s.filter_horizontal[%d]' must be "
                        "a ManyToManyField." % (cls.__name__, idx))

    @cached_property
    def databases(self):
        if self._databases is None:
            self._databases = settings.DATABASES
        if self._databases == {}:
            self._databases = {
                DEFAULT_DB_ALIAS: {
                    'ENGINE': 'django.db.backends.dummy',
                },
            }
        if DEFAULT_DB_ALIAS not in self._databases:
            raise ImproperlyConfigured("You must define a '%s' database" % DEFAULT_DB_ALIAS)
        return self._databases

    def get_queryset(self):
        """
        Get the queryset to look an object up against. May not be called if
        `get_object` is overridden.
        """
        if self.queryset is None:
            if self.model:
                return self.model._default_manager.all()
            else:
                raise ImproperlyConfigured("%(cls)s is missing a queryset. Define "
                                           "%(cls)s.model, %(cls)s.queryset, or override "
                                           "%(cls)s.get_queryset()." % {
                                                'cls': self.__clast__.__name__
                                        })
        return self.queryset._clone()

    def __init__(self, *args, **kwargs):
        if not hasattr(settings, 'ENCRYPTED_FIELD_KEYS_DIR'):
            raise ImproperlyConfigured('You must set the settings.ENCRYPTED_FIELD_KEYS_DIR '
                                       'setting to your Keyczar keys directory.')
        crypt_clast = self.get_crypt_clast()
        self.crypt = crypt_clast.Read(settings.ENCRYPTED_FIELD_KEYS_DIR)

        # Encrypted size is larger than unencrypted
        self.unencrypted_length = max_length = kwargs.get('max_length', None)
        if max_length:
            kwargs['max_length'] = self.calculate_crypt_max_length(max_length)

        super(BaseEncryptedField, self).__init__(*args, **kwargs)

    def get_queryset(self):
        """
        Get the list of items for this view. This must be an iterable, and may
        be a queryset (in which qs-specific behavior will be enabled).
        """
        if self.queryset is not None:
            queryset = self.queryset
            if hasattr(queryset, '_clone'):
                queryset = queryset._clone()
        elif self.model is not None:
            queryset = self.model._default_manager.all()
        else:
            raise ImproperlyConfigured("'%s' must define 'queryset' or 'model'"
                                       % self.__clast__.__name__)
        return queryset

    def validate_inlines(self, cls, model):
        " Validate inline model admin clastes. "
        from django.contrib.admin.options import BaseModelAdmin
        if hasattr(cls, 'inlines'):
            check_isseq(cls, 'inlines', cls.inlines)
            for idx, inline in enumerate(cls.inlines):
                if not issubclast(inline, BaseModelAdmin):
                    raise ImproperlyConfigured("'%s.inlines[%d]' does not inherit "
                            "from BaseModelAdmin." % (cls.__name__, idx))
                if not inline.model:
                    raise ImproperlyConfigured("'model' is a required attribute "
                            "of '%s.inlines[%d]'." % (cls.__name__, idx))
                if not issubclast(inline.model, models.Model):
                    raise ImproperlyConfigured("'%s.inlines[%d].model' does not "
                            "inherit from models.Model." % (cls.__name__, idx))
                inline.validate(inline.model)
                self.check_inline(inline, model)

    def validate_fields(self, cls, model):
        " Validate that fields only refer to existing fields, doesn't contain duplicates. "
        # fields
        if cls.fields: # default value is None
            check_isseq(cls, 'fields', cls.fields)
            self.check_field_spec(cls, model, cls.fields, 'fields')
            if cls.fieldsets:
                raise ImproperlyConfigured('Both fieldsets and fields are specified in %s.' % cls.__name__)
            if len(cls.fields) > len(set(cls.fields)):
                raise ImproperlyConfigured('There are duplicate field(s) in %s.fields' % cls.__name__)

    def validate_list_select_related(self, cls, model):
        " Validate that list_select_related is a boolean, a list or a tuple. "
        list_select_related = getattr(cls, 'list_select_related', None)
        if list_select_related:
            types = (bool, tuple, list)
            if not isinstance(list_select_related, types):
                raise ImproperlyConfigured("'%s.list_select_related' should be "
                                           "either a bool, a tuple or a list" %
                                           cls.__name__)