Django django-fernet-fields

開発環境 Django1.11
DjangoでDBを暗号化したくて、django-fernet-fieldsを用いて開発しています。
そこでプログラムを実行する際に以下のエラーが発生しました

###発生している問題・エラーメッセージ

'Settings' object has no attribute 'AES_METHOD'

###該当のソースコード

python
1#models.py
2from django.db import models
3from fernet_fields import EncryptedTextField
4class MyModel(models.Model):
5    name = EncryptedTextField()

python
1#settings.py
2INSTALLED_APPS = [
3    'django.contrib.admin',
4    'django.contrib.auth',
5    'django.contrib.contenttypes',
6    'django.contrib.sessions',
7    'django.contrib.messages',
8    'django.contrib.staticfiles',
9    'home',
10
11]
12
13MIDDLEWARE = [
14    'django.middleware.security.SecurityMiddleware',
15    'django.contrib.sessions.middleware.SessionMiddleware',
16    'django.middleware.common.CommonMiddleware',
17    'django.middleware.csrf.CsrfViewMiddleware',
18    'django.contrib.auth.middleware.AuthenticationMiddleware',
19    'django.contrib.messages.middleware.MessageMiddleware',
20    'django.middleware.clickjacking.XFrameOptionsMiddleware',
21]
22
23ROOT_URLCONF = 'testAES.urls'
24
25TEMPLATES = [
26    {
27        'BACKEND': 'django.template.backends.django.DjangoTemplates',
28        'DIRS': [],
29        'APP_DIRS': True,
30        'OPTIONS': {
31            'context_processors': [
32                'django.template.context_processors.debug',
33                'django.template.context_processors.request',
34                'django.contrib.auth.context_processors.auth',
35                'django.contrib.messages.context_processors.messages',
36            ],
37        },
38    },
39]
40
41WSGI_APPLICATION = 'testAES.wsgi.application'
42
43
44# Database
45# https://docs.djangoproject.com/en/1.10/ref/settings/#databases
46
47DATABASES = {
48    'default': {
49        'ENGINE': 'django.db.backends.sqlite3',
50        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
51    }
52}
53
54
55# Password validation
56# https://docs.djangoproject.com/en/1.10/ref/settings/#auth-password-validators
57
58AUTH_PASSWORD_VALIDATORS = [
59    {
60        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
61    },
62    {
63        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
64    },
65    {
66        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
67    },
68    {
69        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
70    },
71]
72
73
74# Internationalization
75# https://docs.djangoproject.com/en/1.10/topics/i18n/
76
77LANGUAGE_CODE = 'ja'
78
79TIME_ZONE = 'UTC'
80
81USE_I18N = True
82
83USE_L10N = True
84
85USE_TZ = True
86
87
88# Static files (CSS, JavaScript, Images)
89# https://docs.djangoproject.com/en/1.10/howto/static-files/
90
91STATIC_URL = '/static/'
92