unrecognized arguments: --username appuser when When I try to run the createsuperuser command

Question

My code

class UserManager(BaseUserManager):
    use_in_migrations = True

    def _create_user(self, email, password, **extra_fields):
        if not email:
            raise ValueError("email field is required")
        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, **extra_fields):
        extra_fields.setdefault("is_staff", False)
        extra_fields.setdefault("is_superuser", 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_superuser", True)
        extra_fields.setdefault("username", None)

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


class User(AbstractUser):
    username = "user"
    email = models.EmailField('email adress', unique=True)
    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = []

    class Meta:
        db_table = "USER"

Note that my user must only authenticate with his email and password. Terminal outpout
usage: manage.py createsuperuser [-h] [--email EMAIL] [--noinput] [--database DATABASE] [--version] [-v {0,1,2,3}] [--settings SETTINGS] [--pythonpath PYTHONPATH] [--traceback] [--no-color] [--force-color] [--skip-checks] manage.py createsuperuser: error: unrecognized arguments: --username appuser