Comment je dois regler ce probleme dans mon code'NoneType' object has no attribute 'is_admin'

from django.db import models from django.contrib.auth.base_user import AbstractBaseUser,BaseUserManager

class UsagerManager(BaseUserManager): def create_user(self, email, password=None): если нет электронной почты: raise ValueError("Вы должны ввести действительный email или действительный телефон")

        user = self.model(
            email=self.normalize_email(email)
        )
        user.set_password(password)
        user.save()
        return user



def create_superuser(self, email, password = None):
    user = self.create_user(email=email, password=password)
    user.is_admin = True
    user.is_staff = True
    user.save()
    return user

class UsagerClient(AbstractBaseUser):

CHOISI = [
    ('Atl', 'Atlantique'),
    ('Ata','Atacora'),
    ('Ali', 'Alibori'),
    ('Bor', 'Borgou'),
    ('Cou', 'Couffo'),
    ('Col', 'Colline'),
    ('Don', 'Donga'),
    ('Lit', 'Littoral'),
    ('Mon', 'Mono'),
    ('Oue', 'Oueme'),
    ('Pla', 'Plateau'),
    ('Zou', 'Zou')
]


nom = models.CharField(max_length=50)
prénom = models.CharField(max_length=100)
téléphone = models.CharField(max_length=8)
societe = models.CharField(max_length=15)
email = models.EmailField(unique=True, max_length=255, blank=False)
is_active = models.BooleanField(default=True)
is_staff = models.BooleanField(default=False)
is_admin = models.BooleanField(default=False)
département = models.CharField(max_length=30, choices=CHOISI)
ville = models.CharField(max_length=3)
adresse = models.CharField(max_length=50)

USERNAME_FIELD = "email"
objects = UsagerManager()
REQUIREMENT_FIELD = ["nom", "prénom", "téléphone", "email", "département","ville", "adresse"]


def has_perm(self, perm, obj=None):
    return True

def has_module_perms(self, app_label):
    return True

class UsagerManager(BaseUserManager):
    use_in_migrations = True

    def _create_user(self, email, password, **extra_fields):
        """
        Create and save a user with the given email, and password.
        """
        if not email:
            raise ValueError('The given email must be set')
        email = self.normalize_email(email)
        user = self.model(email=email, **extra_fields)
        user.set_password(password)
        user.save(using=self._db)
        return user

    def create_user(self, email, password=None, **extra_fields):
        extra_fields.setdefault('is_staff', False)
        extra_fields.setdefault('is_admin', False)
        return self._create_user(email, password, **extra_fields)

    def create_superuser(self, email, password, **extra_fields):
        extra_fields.setdefault('is_staff', True)
        extra_fields.setdefault('is_admin', True)

        if extra_fields.get('is_staff') is not True:
            raise ValueError('Superuser must have is_staff=True.')
        if extra_fields.get('is_admin') is not True:
            raise ValueError('Superuser must have is_admin=True.')
        return self._create_user(email, password, **extra_fields)