old_contents: from django.db import models
  
  # Create your models here.
  class BarterEvent(models.Model):
  	barter_account = models.ForeignKey(
  		'BarterAccount',
  		#on_delete=models.CASCADE,
  	)
  	ADD = 'Add'
  	SUBTRACT = 'Subtract'
  	NOTE = 'Note'
  	EVENT_TYPE_CHOICES = (
  		(ADD, 'Add'),
  		(SUBTRACT, 'Subtract'),
  		(NOTE, 'Note'),
  	)
  	event_type = models.CharField(
  		max_length=20,
  		choices = EVENT_TYPE_CHOICES,
  		default = SUBTRACT,
  	)
  	event_time = models.DateTimeField(auto_now_add=True)
  	#staff_id = models.ForeignKey()
  
  class BarterAccount(models.Model):
  	patron_name = models.CharField(max_length=100)
  	balance = models.DecimalField(max_digits=5, decimal_places=2)
  	
new_contents: from django.db import models
  
  # Create your models here.
  class BarterEvent(models.Model):
  	barter_account = models.ForeignKey(
  		'BarterAccount',
  		#on_delete=models.CASCADE,
  	)
  	ADD = 'Add'
  	SUBTRACT = 'Subtract'
  	NOTE = 'Note'
  	EVENT_TYPE_CHOICES = (
  		(ADD, 'Add'),
  		(SUBTRACT, 'Subtract'),
  		(NOTE, 'Note'),
  	)
  	event_type = models.CharField(
  		max_length=20,
  		choices = EVENT_TYPE_CHOICES,
  		default = SUBTRACT,
  	)
  	event_time = models.DateTimeField(auto_now_add=True)
  	#staff_id = models.ForeignKey()
  
  class BarterAccount(models.Model):
  	customer_name = models.CharField(max_length=100)
  	balance = models.DecimalField(max_digits=5, decimal_places=2)
  	
subject: Change 'patron' to 'customer' in BarterAccount