old_contents: from django.db import models
  from django.contrib.auth.models import User
  from django.db.models.signals import post_save
  
  class UserProfile(models.Model):
      user = models.OneToOneField(User)
      pointer = models.IntegerField()
  
  class ZephyrClass(models.Model):
      name = models.CharField(max_length=30)
  
  class Recipient(models.Model):
      user_or_class = models.IntegerField()
      type = models.CharField(max_length=30)
  
  class Zephyr(models.Model):
      sender = models.ForeignKey(UserProfile)
      recipient = models.ForeignKey(Recipient) # personal or class
      instance = models.CharField(max_length=30)
      content = models.CharField(max_length=200)
      pub_date = models.DateTimeField('date published')
  
  def create_user_profile(sender, **kwargs):
      """When creating a new user, make a profile for him or her."""
      u = kwargs["instance"]
      if not UserProfile.objects.filter(user=u):
          UserProfile(user=u, pointer=-1).save()
  post_save.connect(create_user_profile, sender=User)
  
new_contents: from django.db import models
  from django.contrib.auth.models import User
  from django.db.models.signals import post_save
  
  class UserProfile(models.Model):
      user = models.OneToOneField(User)
      pointer = models.IntegerField()
  
  class ZephyrClass(models.Model):
      name = models.CharField(max_length=30)
  
  class Recipient(models.Model):
      user_or_class = models.IntegerField()
      type = models.CharField(max_length=30)
  
  class Zephyr(models.Model):
      sender = models.ForeignKey(UserProfile)
      recipient = models.ForeignKey(Recipient) # personal or class
      instance = models.CharField(max_length=30)
      content = models.CharField(max_length=200)
      pub_date = models.DateTimeField('date published')
  
  def create_user_profile(**kwargs):
      """When creating a new user, make a profile for him or her."""
      u = kwargs["instance"]
      if not UserProfile.objects.filter(user=u):
          UserProfile(user=u, pointer=-1).save()
  post_save.connect(create_user_profile, sender=User)
  
subject: Remove unnecessary create_user_profile argument.