无法分配“'5'”：“ user.clearance”必须是“ clearance”实例

Question

我正在尝试创建一个使用Django的注册用户页面，并且在添加用户时，遇到了一个问题，该问题一直按照本文标题返回。我在下面发布了一些作品。如果有人可以帮助我并告诉我哪里出了问题，我将不胜感激。

this is my views.py

    if request.method == 'POST':
        form = UserRegisterForm(request.POST)
        if form.is_valid():
            form.save()
            username = form.cleaned_data.get('username')
            pwd = make_password(form.cleaned_data.get('password1'))
            mail = form.cleaned_data.get('userEmail')
            fname = form.cleaned_data.get('firstname')
            lname = form.cleaned_data.get('lastname')
            contact = form.cleaned_data.get('userContact')
            company = form.cleaned_data['company']
            clearance = form.cleaned_data['clearance']
            args = (username, pwd, mail,fname, lname, contact, company, clearance)
            db = MySQLdb.connect(host=var.host, user=var.user, password=var.password, db=var.db)
            cur = db.cursor()
            cur.callproc('sp_NewSignUp', args)
            db.commit()
            cur.close()
            db.close()
            messages.success(request, f'Account created for {username}!')
            return redirect('homepage')
        else:
            print("form error")
    else:
        form = UserRegisterForm()
    return render(request, 'main/register.html', {'form': form})

`````forms.py``````

db = MySQLdb.connect(host=var.host, user=var.user, password=var.password, db=var.db)
cur = db.cursor()
cur.callproc('sp_getClearanceRegister', args='') 
account_choice =  []
for i in cur.fetchall():   
    account_choice.append(i)
cur.nextset()
user = 'root'
companyid = '1'
args = user, companyid
cur.callproc('sp_getUserCompany', args)
company_choice = []
for i in cur.fetchall():   
    company_choice.append(i)
cur.close()
db.close()

class UserRegisterForm(UserCreationForm):
    userEmail = forms.EmailField(label='Email')
    firstname = forms.CharField(label='First Name')
    lastname = forms.CharField(label='Last Name')
    userContact = forms.IntegerField(label='Contact No.')
    clearance = forms.CharField(label='Clearance', widget=forms.Select(choices=account_choice))
    company = forms.CharField(label='Company', widget=forms.Select(choices=company_choice))

    class Meta:
        model  =  get_user_model()
        fields = ['username', 'password1', 'password2','userEmail', 'firstname','lastname', 'userContact', 'clearance', 'company']

models.py

class company(models.Model):
    company_id = models.AutoField('Company ID', primary_key = True)
    company_name = models.CharField('Company Name',max_length=255, unique=True)
    company_address = models.CharField('Company Address', max_length=255)
    company_email = models.CharField('Company Email', max_length=255)
    company_contact = models.CharField('Company Contact Info', max_length=45)
    date_of_creation = models.DateTimeField('Date Company Joined')
    date_of_lastModified = models.DateTimeField('Date Of Company Info Last Modified')
    class Meta:
        verbose_name_plural = "company"

    def __str__(self):
        return self.company_name

class clearance(models.Model):
    clearance_id = models.AutoField('Clearance ID', primary_key = True)
    clearance_name = models.CharField('Clearance Name', max_length=45, unique=True)
    clearance_level = models.IntegerField('Clearance Level')
    date_of_creation = models.DateTimeField('Date Clearance Added')
    date_of_last_modified = models.DateTimeField('Date Of Clearance Last Modified')

    class Meta:
        verbose_name_plural = "clearance"

    def __str__(self):
        return self.clearance_name

class user(AbstractUser):
    user_id = models.AutoField('User ID', primary_key = True)
    user_contact = models.CharField('Contact', max_length=45)
    clearance = models.ForeignKey(clearance, default = 1, verbose_name = "Clearance ID", on_delete = models.SET_DEFAULT)
    company = models.ForeignKey(company, default = 1, verbose_name = "Company ID", on_delete = models.SET_DEFAULT)

    #objects = UserManager()

    class Meta:
        verbose_name_plural = "user"

    def __str__(self):
        return self.username

最初，添加用户直到更改为abstractuser都没问题。并且我收到此错误消息，指出

无法分配“'5'”：“ user.clearance”必须是“ clearance”实例。”

我觉得符号“ 5”存在一些问题，但我不知道如何解决。