[Django]FormViewを使用したアカウント作成処理でエラーが発生する。

前提・実現したいこと

DjangoでBLOGを作成しております。

FormViewを利用して
アカウント作成の処理を書いておりますが、以下エラーが発生しております。
init() takes 1 positional argument but 2 were given

前提条件として何か必要でしょうか。

発生している問題・エラーメッセージ

TypeError at /user/add
__init__() takes 1 positional argument but 2 were given
Request Method:	GET
Request URL:	http://localhost:8080/user/add
Django Version:	3.0.8
Exception Type:	TypeError
Exception Value:	
__init__() takes 1 positional argument but 2 were given
Exception Location:	/usr/local/lib64/python3.6/site-packages/django/core/handlers/base.py in _get_response, line 113
Python Executable:	/usr/bin/python3
Python Version:	3.6.8
Python Path:	
['/var/www/html/wto_web_app',
 '/usr/lib64/python36.zip',
 '/usr/lib64/python3.6',
 '/usr/lib64/python3.6/lib-dynload',
 '/usr/local/lib64/python3.6/site-packages',
 '/usr/local/lib/python3.6/site-packages',
 '/usr/lib64/python3.6/site-packages',
 '/usr/lib/python3.6/site-packages']

Internal Server Error: /user/add
Traceback (most recent call last):
  File "/usr/local/lib64/python3.6/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/usr/local/lib64/python3.6/site-packages/django/core/handlers/base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/usr/local/lib64/python3.6/site-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
TypeError: __init__() takes 1 positional argument but 2 were given

該当のソースコード

Django
1### user/view.py
2class UserAdd(FormView):
3    context_object_name = 'add_user'
4    template_name = 'user/user_add.html'
5    form_class = UserAddForm
6
7    def form_valid(self, form):
8        password = form.cleaned_data.get('password')
9        user = User.objects.create_user(
10            screen_id = form.cleaned_data.get('screen_id'),
11            email = form.cleaned_data.get('email'),
12            password = password
13        )
14        user.icon = form.cleaned_data.get('icon')
15        user.screen_name = form.cleaned_data.get('screen_name')
16        user.full_name = form.cleaned_data.get('full_name')
17        user.full_kana = form.cleaned_data.get('full_kana')
18        user.resident_flag = form.cleaned_data.get('resident_flag')
19        user.notification_flag = form.cleaned_data.get('notification_flag')
20        user.city = form.cleaned_data.get('country')
21        user.save()
22        return super().form_valid(form)
23
24    def form_invalid(self, form):
25        return super().form_invalid(form)
26
27    def get_success_url(self):
28        return reverse_lazy('top_page')
29

Django
1### user/forms.py
2class UserAddForm(forms.Form):
3
4    # アイコン
5    icon = forms.ImageField(
6        label='アイコン',
7        widget=forms.TextInput(), #あとで
8        required=False, # defであとで定義
9    )
10
11    # ユーザー名
12    screen_name = forms.CharField(
13        label='ユーザー名',
14        max_length=30,
15        widget=forms.TextInput(),
16        error_messages={
17            'required': get_error_message(message='required_user_screen_name'),
18        }
19    )
20
21    # ID
22    screen_id = forms.CharField(
23        label='ID',
24        widget=forms.TextInput(),
25        max_length=30,
26        min_length=6,
27        error_messages={
28            'required': get_error_message(message='required_user_screen_id'),
29            'min_length': get_error_message(message='min_length',num='6')
30        }
31    )
32
33    # 氏名
34    full_name = forms.CharField(
35        label='氏名',
36        max_length=60,
37        error_messages={
38            'required': get_error_message(message='required_user_name'),
39        }
40    )
41
42    # フリガナ
43    full_kana = forms.CharField(
44        label='フリガナ',
45        max_length=60,
46        error_messages={
47            'required': get_error_message(message='required_user_kana'),
48        }
49    )
50
51    # メールアドレス
52    email = forms.CharField(
53        label='メールアドレス',
54        max_length=255,
55        widget=forms.TextInput(),
56        error_messages={
57            'required': get_error_message(message='required_user_email'),
58            'max_length': get_error_message(message='max_length',num='128')
59        }
60    )
61
62    # 海外在住フラグ
63    resident_flag = forms.ChoiceField(
64        label= '海外在住の有無',
65        widget=forms.RadioSelect,
66        choices=RESIDENT_CHOICE,
67    )
68
69    # 通知フラグ
70    notification_flag = forms.ChoiceField(
71        label= '通知',
72        widget=forms.RadioSelect,
73        choices=NOTIFICATION_CHOICE,
74    )
75
76    # パスワード
77    password = forms.CharField(
78        label='パスワード',
79        widget=forms.PasswordInput(),
80        max_length=30,
81        min_length=10,
82        error_messages={
83            'required': get_error_message(message='required_password'),
84        }
85    )
86
87    # パスワード確認
88    password_verification = forms.CharField(
89        label='パスワード確認',
90        widget=forms.PasswordInput(),
91        max_length=30,
92        min_length=10,
93        error_messages={
94            'required': get_error_message(message='required_password_verification'),
95        }
96    )
97
98    # 興味のある国
99    country=forms.MultipleChoiceField(
100        label='興味のある国',
101        required=False,
102        widget=forms.CheckboxSelectMultiple
103    )
104
105    def __init__(self, *args, **kwargs):
106        super().__init__(*args, **kwargs)
107        # 国リスト
108        countries = City.objects.all()
109        list = []
110        for country in countries:
111            list.append((str(country.pk),country.country_name))
112        self.fields['country'].choices = list
113