old_contents: from django.db import models
  
  
  class Tag(models.Model):
      name = models.CharField(max_length=100,
                              unique=True)
  
  class Article(models.Model):
      slug = models.CharField(max_length=100,
                              unique=True)
      title = models.CharField(max_length=255)
      created_at = models.DateTimeField(auto_now_add=True)
      updated_at = models.DateTimeField(auto_now=True)
      content = models.TextField()
      active = models.BooleanField()
      tags = models.ManyToManyField(Tag)
new_contents: from django.db import models
  
  
  class Tag(models.Model):
      name = models.CharField(max_length=100,
                              unique=True)
  
      def __str__(self):
          return self.name
  
  
  class Article(models.Model):
      slug = models.CharField(max_length=100,
                              unique=True)
      title = models.CharField(max_length=255)
      created_at = models.DateTimeField(auto_now_add=True)
      updated_at = models.DateTimeField(auto_now=True)
      content = models.TextField()
      active = models.BooleanField()
      tags = models.ManyToManyField(Tag)
  
      def __str__(self):
          return self.title
subject: Implement string function on models