Поле 'last_login' ожидало число, но получило время даты

hello Я столкнулся с этой проблемой при попытке подключиться к Django Admin вот мой исходный код Я не хочу изменять поле last_login моей старой таблицы пользователей в дате времени это целочисленное поле, которое останавливает дату времени в unix timestamp. вот мой исходный код

from django.db import models
from django.contrib.auth.models import AbstractBaseUser,BaseUserManager
from .helper import get_current_unix_timestamp
from django.contrib.auth.signals import user_logged_in


class MyUserManager(BaseUserManager):
    def create_user(self, username,password=None):
        """
        Creates and saves a User with the given email, date of
        birth and password.
        """
        if not username:
            raise ValueError('user must have a username')

        user = self.model(
            username=username,
        )

        user.set_password(password)
        user.save(using=self._db)
        return user

    def create_superuser(self, username, password=None):
        """
        Creates and saves a superuser with the given email, date of
        birth and password.
        """
        user = self.create_user(
            username,
            password=password,
        )
        user.is_admin = True
        user.is_superuser = True
        user.is_staff = True
        user.save(using=self._db)
        return user

class Account(AbstractBaseUser):
    id = models.AutoField(primary_key=True,verbose_name='ID',)
    username = models.CharField(max_length=50, blank=True, null=True,unique=True)
    password = models.CharField(max_length=255, blank=True, null=True)
    email = models.CharField(max_length=255, blank=True, null=True)
    ip = models.CharField(max_length=255,null=True,blank=True)
    date_registered = models.IntegerField(default=get_current_unix_timestamp())
    last_login = models.IntegerField(null=True,blank=True)
    member_group_id = models.IntegerField(blank=True, null=True)
    credits = models.FloatField(blank=True, null=True)
    notes = models.TextField(blank=True, null=True)
    status = models.IntegerField(blank=True, null=True)
    reseller_dns = models.TextField(blank=True, null=True)
    owner_id = models.IntegerField(blank=True, null=True)
    override_packages = models.TextField(blank=True, null=True)
    hue = models.CharField(max_length=50, blank=True, null=True)
    theme = models.IntegerField(blank=True, null=True)
    timezone = models.CharField(max_length=255, blank=True, null=True)
    api_key = models.CharField(max_length=64, blank=True, null=True)
    is_admin = models.BooleanField(default=False)
    is_superuser = models.BooleanField(default=False)
    is_staff = models.BooleanField(default=False)
    is_active = models.BooleanField(default=True)
    objects = MyUserManager()
    USERNAME_FIELD = 'username'


    class Meta:
        managed = True
        db_table = 'users'
        ordering = ['username']

    def __str__(self):
        return self.username
def update_last_login(sender, user, **kwargs):
    """
    A signal receiver which updates the last_login date for
    the user logging in.
    """
    user.last_login = get_current_unix_timestamp()
    user.save(update_fields=['last_login'])


user_logged_in.send(update_last_login)

исходный код функции get_current_unix_timestamp импортировать datetime

def get_current_unix_timestamp():
    """this function retrun a unix format datetime"""
    return int(datetime.datetime.now().strftime('%s'))

# app_name/fields.py

from django.db.models.fields import IntegerField
from time import mktime

class DateTimeIntegerField(IntegerField):

    def get_prep_value(self, value):
        if isinstance(value, date):
            value = mktime(value.timetuple())
        return super().get_prep_value(value)

    def to_python(self, value):
        if isinstance(value, date):
            value = mktime(value.timetuple())
        return super().to_python(value)

from app_name.fields import DateTimeIntegerField

class Account(AbstractBaseUser):
    # …,
    last_login = DateTimeIntegerField(null=True,blank=True)
    # …