How instanciate table in createsuperuser

I have two tables Employee and Sector, the employee table has for foreign key the sector code (sectorCode) property of the Sector table. The Employee table inherits from the AbstractBaseUser class.
I would like to create a superuser with the command python manage.py createsuperuser.
I get an error: ValueError: Cannot assign "'Code1'": "Employee.sectorCode" must be a "Sector" instance.
(I added in the Sector table a row NameSector1; Code1)

I input these values:

λ python manage.py createsuperuser
registrationNumber: 001
Name: TestN1
FirstName: TestFN1
sectorCode: Code1
Password: ...

Error ...

How can I instantiate sector class in dialog ?

models.py

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

class MyUserManager(BaseUserManager):
    
    def create_user(self, registrationNumber, firstName, name, sectorCode, password=None):
        if not firstName: raise ValueError("firstName required")
        if not name: raise ValueError("name required")
        if not registrationNumber: raise ValueError("registrationNumber required")
        if not sectorCode: raise ValueError("sectorCode required")
        
        user=self.model(firstName = firstName, name = name, registrationNumber = registrationNumber, sectorCode = sectorCode)
        user.set_password(password); user.save()
        return user
    
    def create_superuser(self, firstName, name, registrationNumber, sectorCode, password=None):
        user=self.create_user(firstName = firstName, name = name, registrationNumber = registrationNumber, sectorCode = sectorCode, password = password)
        user.is_admin=True; user.is_superuser=True
        user.save()
        return user

class Sector(models.Model):
    nameSector = models.CharField(verbose_name = "nameSector", max_length=50)
    sectorCode = models.CharField(verbose_name = "sectorCode", max_length=3, primary_key=True)
    
    class Meta: db_table = "Sector"
    
class Employee(AbstractBaseUser):
    firstName = models.CharField(verbose_name = "firstName", max_length=20)
    name = models.CharField(verbose_name = "name", max_length=20)
    registrationNumber = models.CharField(verbose_name="registrationNumber", max_length=20, primary_key=True)
    sectorCode = models.ForeignKey(Sector, on_delete=models.CASCADE)
    
    USERNAME_FIELD="registrationNumber"
    REQUIRED_FIELDS = ["name", "firstName", "sectorCode"]
    objects = MyUserManager()
    class Meta: db_table = "Employee"

>Solution :

If you know the sector exists, you can work with:

class MyUserManager(BaseUserManager):
    def create_user(
        self, registrationNumber, firstName, name, sectorCode, password=None
    ):
        if not firstName:
            raise ValueError("firstName required")
        if not name:
            raise ValueError("name required")
        if not registrationNumber:
            raise ValueError("registrationNumber required")
        if not sectorCode:
            raise ValueError("sectorCode required")

        user = self.model(
            firstName=firstName,
            name=name,
            registrationNumber=registrationNumber,
            sectorCode_id=sectorCode,
        )
        user.set_password(password)
        user.save()
        return user

    # …

If you want to create a Sector in case that one is missing, you can use:

class MyUserManager(BaseUserManager):
    def create_user(
        self, registrationNumber, firstName, name, sectorCode, password=None
    ):
        if not firstName:
            raise ValueError("firstName required")
        if not name:
            raise ValueError("name required")
        if not registrationNumber:
            raise ValueError("registrationNumber required")
        if not sectorCode:
            raise ValueError("sectorCode required")

        sector, __ = Sector.objects.get_or_create(
            sectorCode=sectorCode, defaults={'nameSector': sectorCode}
        )

        user = self.model(
            firstName=firstName,
            name=name,
            registrationNumber=registrationNumber,
            sectorCode=sector,
        )
        user.set_password(password)
        user.save()
        return user

    # …

Code1 will however not be valid, since the sector code has a maximum length of three characters.

Note: normally the name of the fields in a Django model are written in snake_case, not PascalCase, so it should be: first_name instead of firstName.