old_contents: import uuid
  
  from django.db import models
  from django.contrib.auth.models import User
  from django.contrib.postgres.fields import JSONField
  from django.utils.encoding import python_2_unicode_compatible
  
  from registrations.models import Source
  
  
  @python_2_unicode_compatible
  class Change(models.Model):
      """ A request to change a subscription
  
      Args:
          registrant_id (str): UUID of the registrant's identity
          action (str): What type of change to implement
          data (json): Change info in json format
          source (object): Auto-completed field based on the Api key
      """
  
      ACTION_CHOICES = (
          ('baby_switch', "Change from pregnancy to baby messaging"),
          ('pmtct_loss_switch', "Change to loss messaging via pmtct app"),
          ('pmtct_loss_optout', "Optout due to loss via pmtct app"),
          ('pmtct_nonloss_optout', "Optout not due to loss via pmtct app"),
          ('nurse_update_detail', "Update nurseconnect detail"),
          ('nurse_change_msisdn', "Change nurseconnect msisdn"),
          ('nurse_optout', "Optout from nurseconnect"),
          ('momconnect_loss_switch',
              "Change to loss messaging via momconnect app"),
          ('momconnect_loss_optout', "Optout due to loss via momconnect app"),
          ('momconnect_nonloss_optout',
              "Optout not due to loss via momconnect app"),
          ('momconnect_change_language',
              "Change the language of the messages via momconnect app"),
      )
  
      id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
      registrant_id = models.CharField(max_length=36, null=False, blank=False)
      action = models.CharField(max_length=255, null=False, blank=False,
                                choices=ACTION_CHOICES)
      data = JSONField(null=True, blank=True)
      validated = models.BooleanField(default=False)
      source = models.ForeignKey(Source, related_name='changes',
                                 null=False)
      created_at = models.DateTimeField(auto_now_add=True)
      updated_at = models.DateTimeField(auto_now=True)
      created_by = models.ForeignKey(User, related_name='changes_created',
                                     null=True)
      updated_by = models.ForeignKey(User, related_name='changes_updated',
                                     null=True)
      user = property(lambda self: self.created_by)
  
      def __str__(self):
          return str(self.id)
  
new_contents: import uuid
  
  from django.db import models
  from django.contrib.auth.models import User
  from django.contrib.postgres.fields import JSONField
  from django.utils.encoding import python_2_unicode_compatible
  
  from registrations.models import Source
  
  
  @python_2_unicode_compatible
  class Change(models.Model):
      """ A request to change a subscription
  
      Args:
          registrant_id (str): UUID of the registrant's identity
          action (str): What type of change to implement
          data (json): Change info in json format
          source (object): Auto-completed field based on the Api key
      """
  
      ACTION_CHOICES = (
          ('baby_switch', "Change from pregnancy to baby messaging"),
          ('pmtct_loss_switch', "Change to loss messaging via pmtct app"),
          ('pmtct_loss_optout', "Optout due to loss via pmtct app"),
          ('pmtct_nonloss_optout', "Optout not due to loss via pmtct app"),
          ('nurse_update_detail', "Update nurseconnect detail"),
          ('nurse_change_msisdn', "Change nurseconnect msisdn"),
          ('nurse_optout', "Optout from nurseconnect"),
          ('momconnect_loss_switch',
              "Change to loss messaging via momconnect app"),
          ('momconnect_loss_optout', "Optout due to loss via momconnect app"),
          ('momconnect_nonloss_optout',
              "Optout not due to loss via momconnect app"),
          ('momconnect_change_language',
              "Change the language of the messages via momconnect app"),
          ('momconnect_change_msisdn',
              "Change the MSISDN to send messages to via momconnect app"),
      )
  
      id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
      registrant_id = models.CharField(max_length=36, null=False, blank=False)
      action = models.CharField(max_length=255, null=False, blank=False,
                                choices=ACTION_CHOICES)
      data = JSONField(null=True, blank=True)
      validated = models.BooleanField(default=False)
      source = models.ForeignKey(Source, related_name='changes',
                                 null=False)
      created_at = models.DateTimeField(auto_now_add=True)
      updated_at = models.DateTimeField(auto_now=True)
      created_by = models.ForeignKey(User, related_name='changes_created',
                                     null=True)
      updated_by = models.ForeignKey(User, related_name='changes_updated',
                                     null=True)
      user = property(lambda self: self.created_by)
  
      def __str__(self):
          return str(self.id)
  
subject: Add change momconnect msisdn change type