在Django中更改错误消息

Question

我想更改错误消息，但我不能尝试下面的方法。这对我没有用。

https://stackoverflow.com/a/8977228/6584242

https://stackoverflow.com/a/3437158/6584242

我的模特

class Contact(models.Model):
isim = models.CharField(max_length =120, blank =False, null =True,error_messages={'required': 'Bu alan doldurulmalidir'})
soyad = models.CharField(max_length =120, blank =False, null =True,default='Burasi doldurulmalidir',error_messages={'required': 'Bu alan doldurulmalidir'})
kurum = models.CharField(max_length =120, blank =False, null =False,default='Burasi doldurulmalidir',error_messages={'required': 'Bu alan doldurulmalidir'})
bolum = models.CharField(max_length =120, blank =False, null =False,default='Burasi doldurulmalidir',error_messages={'required': 'Bu alan doldurulmalidir'})
....
def __unicode__(self):
    return unicode(self.user)

我的表格

class ContactForm(forms.ModelForm):
class Meta:
    model = Contact
    fields = ['unvan','isim','soyad','kurum',"bolum","gorev", "uzmanlik","adres","posta_kodu","sehir","ulke","is_tel","ev_tel","fax_no","cep_tel"]
    field_args = {
        "isim" : {
            "error_messages" : {
                "required" : "Please let us know what to call you!"
            }
        }
    }

我哪里弄错了？

提前致谢