code: def _create_user(self, email, password, **extra_fields):
          
          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
docs: Create and save a User with the given email and password.