old_contents: from django.db import models
  
  
  class Chart(models.Model):
  	title = models.CharField(max_length=50)
  	url = models.CharField(max_length=1024)
  
  	def __unicode__(self):
  		return self.title
  
  
  class Page(models.Model):
  	title = models.CharField(max_length=50)
  	slug = models.SlugField()
  	charts = models.ManyToManyField(Chart)
  
  	time_from = models.CharField(max_length=50, default=u"-24h")
  	time_until = models.CharField(max_length=50, default=u"", blank=True)
  
  	image_width = models.PositiveIntegerField(default=1200)
  	image_height = models.PositiveIntegerField(default=400)
  
  	def __unicode__(self):
  		return self.title
  		
  	def get_absolute_url(self):
  	    return reverse('page_detail', kwargs={'slug': self.slug})
  
new_contents: from django.db import models
  from django.core.urlresolvers import reverse
  
  
  class Chart(models.Model):
  	title = models.CharField(max_length=50)
  	url = models.CharField(max_length=1024)
  
  	def __unicode__(self):
  		return self.title
  
  
  class Page(models.Model):
  	title = models.CharField(max_length=50)
  	slug = models.SlugField()
  	charts = models.ManyToManyField(Chart)
  
  	time_from = models.CharField(max_length=50, default=u"-24h")
  	time_until = models.CharField(max_length=50, default=u"", blank=True)
  
  	image_width = models.PositiveIntegerField(default=1200)
  	image_height = models.PositiveIntegerField(default=400)
  
  	def __unicode__(self):
  		return self.title
  		
  	def get_absolute_url(self):
  	    return reverse('page_detail', kwargs={'slug': self.slug})
  
subject: Add missing 'reverse' import