Cannot create super user use custom user model in django 1.8

i try to make custom user model and i want to make super user but i am getting error like this

Traceback (most recent call last): File "manage.py", line 10, in <module> execute_from_command_line(sys.argv) File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 338, in execute_from_command_line utility.execute() File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 330, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 390, in run_from_argv self.execute(*args, **cmd_options) File "/usr/local/lib/python2.7/dist-packages/django/contrib/auth/management/commands/createsuperuser.py", line 50, in execute return super(Command, self).execute(*args, **options) File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 441, in execute output = self.handle(*args, **options) File "/usr/local/lib/python2.7/dist-packages/django/contrib/auth/management/commands/createsuperuser.py", line 149, in handle self.UserModel._default_manager.db_manager(database).create_superuser(**user_data) TypeError: create_superuser() takes exactly 4 arguments (3 given) 

this is my model.py

class MyUserManager(BaseUserManager): def create_user(self, username, email, password=None): if not email: raise ValueError('Users must have an email address') user = self.model( email = self.normalize_email(email), username = username, ) user.set_password(password) user.save(using=self._db) return user def create_superuser(self, username, email, password): user = self.create_user(email,username=username, password=password) user.is_admin = True user.save(using=self._db) return user class Operator(AbstractBaseUser, PermissionsMixin): owner = models.ForeignKey('Owner') kontraktor = models.ForeignKey('Kontraktor') alphanumeric = RegexValidator(r'^[0-9a-zA-Z]*$', message='hanya yang mengandung karakter alphanumeric') email = models.EmailField(verbose_name='email address', unique=True, max_length=244) username = models.CharField(unique=True, max_length=20, validators=[alphanumeric]) first_name = models.CharField(max_length=30, null=True, blank=True) last_name = models.CharField(max_length=30, null=True, blank=True) date_of_birth = models.DateTimeField(auto_now_add=True) date_joined = models.DateTimeField(auto_now_add=True) is_active = models.BooleanField(default=True, null=False) is_staff = models.BooleanField(default=False, null=False) objects = MyUserManager() USERNAME_FIELD = 'email' REQUIRED_FIELD = ['username'] def get_full_name(self): fullname = self.first_name+" "+self.last_name return self.fullname def get_short_name(self): return self.username def __str__(self): return self.email 

can you help me solve this problem?