old_contents: from django.contrib.auth.models import User
  from django.db import models
  
  
  class MonFile(models.Model):
      name = models.CharField(max_length=100, null=True, blank=True)
      file = models.FileField(max_length=100, upload_to='monfile/%Y-%m-%d')
  
      description = models.TextField(null=True, blank=True)
      user = models.ForeignKey(User, default=1, related_name='user_files')
  
      # automatic fields
      created_at = models.DateTimeField(auto_now_add=True, help_text=u'Created')
      updated_at = models.DateTimeField(auto_now=True, help_text=u'Updated')
  
  
  class MonAlbum(models.Model):
      name = models.CharField(max_length=250)
      description = models.TextField(blank=True)
      cover = models.ForeignKey(MonFile,
                                null=True,
                                blank=True,
                                on_delete=models.SET_NULL)
      files = models.ManyToManyField(MonFile,
                                     related_name='albums',
                                     blank=True)
new_contents: from django.contrib.auth.models import User
  from django.db import models
  
  
  class MonFile(models.Model):
      name = models.CharField(max_length=100, null=True, blank=True)
      file = models.FileField(max_length=100, upload_to='monfile/%Y-%m-%d')
  
      description = models.TextField(null=True, blank=True)
      user = models.ForeignKey(User, default=1, related_name='user_files')
  
      # automatic fields
      created_at = models.DateTimeField(auto_now_add=True, help_text=u'Created')
      updated_at = models.DateTimeField(auto_now=True, help_text=u'Updated')
  
      class Meta:
          verbose_name_plural = 'Mes Files'
  
      def __unicode__(self):
          return self.name
  
  
  class MonAlbum(models.Model):
      name = models.CharField(max_length=250)
      description = models.TextField(blank=True)
      cover = models.ForeignKey(MonFile,
                                null=True,
                                blank=True,
                                on_delete=models.SET_NULL)
      files = models.ManyToManyField(MonFile,
                                     related_name='albums',
                                     blank=True)
  
      class Meta:
          verbose_name_plural = 'Mes Albums'
  
      def __unicode__(self):
          return self.name
  
subject: Add __unicode__ and verbose_name_plural for models