old_contents: from django.contrib.auth.models import User
  
  from django.contrib.gis.db import models
  from django.contrib.gis.geos import Point
  
  defaults = {
      'location': Point(-117.0382, 32.5149, srid=4326),
      'state': 'BC',
      'city': 'Tijuana',
      'country': 'MX',
  }
  
  
  class AddressModel(models.Model):
      """
      An abstract base class model that provides address fields.
      """
  
      number = models.CharField(max_length=30, default="")
      street = models.CharField(max_length=254, default="")
      unit = models.CharField(max_length=30, null=True, blank=True)
      neighborhood = models.CharField(max_length=100, null=True, blank=True)
      city = models.CharField(max_length=100, default=defaults['city'])
      state = models.CharField(max_length=3, default=defaults['state'])
      zipcode = models.CharField(max_length=12, default="")
      country = models.CharField(max_length=2, default=defaults['country'])
  
      location = models.PointField(srid=4326, default=defaults['location'])
  
      class Meta:
          abstract = True
  
  
  class UpdatedByModel(models.Model):
      comment = models.CharField(max_length=254, null=True, blank=True)
      updated_by = models.ForeignKey(User,
                                     on_delete=models.CASCADE)
      updated_on = models.DateTimeField(auto_now=True)
  
      class Meta:
          abstract = True
  
new_contents: from django.contrib.auth.models import User
  
  from django.contrib.gis.db import models
  from django.contrib.gis.geos import Point
  
  defaults = {
      'location': Point(-117.0382, 32.5149, srid=4326),
      'state': 'BCN',
      'city': 'Tijuana',
      'country': 'MX',
  }
  
  
  class AddressModel(models.Model):
      """
      An abstract base class model that provides address fields.
      """
  
      number = models.CharField(max_length=30, default="")
      street = models.CharField(max_length=254, default="")
      unit = models.CharField(max_length=30, null=True, blank=True)
      neighborhood = models.CharField(max_length=100, null=True, blank=True)
      city = models.CharField(max_length=100, default=defaults['city'])
      state = models.CharField(max_length=3, default=defaults['state'])
      zipcode = models.CharField(max_length=12, default="")
      country = models.CharField(max_length=2, default=defaults['country'])
  
      location = models.PointField(srid=4326, default=defaults['location'])
  
      class Meta:
          abstract = True
  
  
  class UpdatedByModel(models.Model):
      comment = models.CharField(max_length=254, null=True, blank=True)
      updated_by = models.ForeignKey(User,
                                     on_delete=models.CASCADE)
      updated_on = models.DateTimeField(auto_now=True)
  
      class Meta:
          abstract = True
  
subject: Change BC to BCN in defaults.