old_contents: 
  from django.core.validators import RegexValidator, MinValueValidator
  from django.db import models
  
  alphanumeric = RegexValidator(r'^[0-9A-Za-z]+$', 'Only alphanumeric characters are allowed.')
  
  class Room(models.Model):
  	title = models.CharField(
          unique=True,
          blank=False,
          null=False,
          max_length=100,
          validators=[alphanumeric],
          help_text="The title of the room (i.e. '2E'). Characters A-Z, 0-9.",
          )
  	unofficial_name = models.CharField(
          blank=True,
          null=True,
          max_length=100,
          help_text="The unofficial name of the room (i.e. 'Starry Night')",
          )
  	description = models.TextField(
          blank=True,
          null=True,
          help_text="The description of this room.",
          )
  	occupancy = models.IntegerField(
          default=1,
          validators=[MinValueValidator(0)],
          help_text="The total number of people that this room should house.",
          )
  
  	def __unicode__(self):
  		return self.title
  
  	def __str__(self):
  		return self.__unicode__()
  
new_contents: """
  Project: Farnsworth
  
  Authors: Karandeep Singh Nagra and Nader Morshed
  """
  
  
  from django.core.validators import RegexValidator, MinValueValidator
  from django.db import models
  
  alphanumeric = RegexValidator(r'^[0-9A-Za-z]+$', 'Only alphanumeric characters are allowed.')
  
  class Room(models.Model):
      """ Model for a resident room in the house. """
  	title = models.CharField(
          unique=True,
          blank=False,
          null=False,
          max_length=100,
          validators=[alphanumeric],
          help_text="The title of the room (i.e. '2E'). Characters A-Z, 0-9.",
          )
  	unofficial_name = models.CharField(
          blank=True,
          null=True,
          max_length=100,
          help_text="The unofficial name of the room (i.e. 'Starry Night')",
          )
  	description = models.TextField(
          blank=True,
          null=True,
          help_text="The description of this room.",
          )
  	occupancy = models.IntegerField(
          default=1,
          validators=[MinValueValidator(0)],
          help_text="The total number of people that this room should house.",
          )
      current_residents = models.ManyToManyField(
          UserProfile,
          null=True,
          blank=True,
          help_text="The current residents of this room."
          )
  
  	def __unicode__(self):
  		return self.title
  
  	def __str__(self):
  		return self.__unicode__()
  
  class PreviousResidence(models.Model):
      """ Model to represent a previous residence in a room. """
      room = models.ForeignKey(
          Room,
          null=False,
          blank=False,
          help_text="The relevant room."
          )
      resident = models.ForeignKey(
          UserProfile,
          null=False,
          blank=False,
          help_text="The resident."
          )
      start_date = models.DateField(
          null=False,
          blank=False,
          auto_now_add=False,
          auto_now=False,
          help-text="Start date of this person's residence in this room."
          )
      end_date = models.DateField(
          null=False,
          blank=False,
          auto_now_add=False,
          auto_now=False,
          help-text="End date of this person's residence in this room."
          )
  
subject: Update models.py