python - Django save method overwritten and type object 'cursos' has no attribute 'object' -

i new django , 'm trying create code of course use later generate code in table.

i have overwritten method save returns error

exception value:     type object 'cursos' has no attribute 'object' 

according other responses problem codigo_curso not being filled yet in example of field slug not require filled field after being recorded in database

import re django.db import models django.utils.text import slugify  # create models here. class cursos(models.model):     nombre = models.charfield(max_length=200, null=false, blank=false)     descripcion = models.textfield(null=false, blank=true)     creado = models.datetimefield(auto_now_add=true, editable=false)     modificado = models.datetimefield(auto_now=true, editable=false)     slug = models.slugfield(editable=false)     codigo_curso = models.charfield(max_length=4, null=false, blank=true, editable=false)      def __unicode__(self):        return u'%s' % (self.nombre,)      def crear_codigo(self):        curso_nombre = str(cursos.object.filter(id=self.id).values('nombre'))        codigo_generado = "".join(item[0].upper() item in re.findall("\w+", curso_nombre)[:4])     return self.codigo_generado      def save(self, *args, **kwargs):         # generacion automatica de slug.         if not self.slug:             self.slug = slugify(self.nombre)[:50]         return super(cursos, self).save(*args, **kwargs)          # generacion automatica de curso         if not self.codigo_curso:            self.codigo_curso = self.crear_codigo()         return super(cursos, self).save(*args, **kwargs) 

i try changing order of functions still find error not problem thanks

the model manager called via objects, not object:

curso_nombre = str(cursos.objects.filter(id=self.id).values('nombre'))                           # here^