code: def _create_user(self, email, password, is_superuser, **extra_fields):
          
          now = timezone.now()
          if not email:
              raise ValueError('The given email must be set')
  
          email = self.normalize_email(email)
          user = self.model(
              email=email,
              password=password,
              is_active=True,
              is_superuser=is_superuser, last_login=now,
              date_joined=now,
              **extra_fields)
          user.set_password(password)
          user.save(using=self._db)
          return user
docs: Create new user