old_contents: from django.db import models
  
  
  class Currency(models.Model):
      name = models.CharField(max_length=25)
      contraction = models.CarField(max_length=5)
      def __str__(self):
          return self.name
  
  
  class Account(models.Model):
      DEFAULT_CURRENCY_ID = 1 # pounds ?
      BANK = 'b'
      CASH = 'c'
      TYPE_CHOICES = (
          (BANK, 'Bank'),
          (CASH, 'Cash'),
      )
      account_type = models.CharField(max_length=5, choices=TYPE_CHOICES, default=CASH)
      bank_name = models.CharField(max_length=25, blank=True)
      number = models.CharField(max_length=140, blank=True)
      balance = models.DecimalField(decimal_places=10, max_digits=19, default=0)
      currency = models.ForeignKey(Currency, default=DEFAULT_CURRENCY_ID)
      active = models.BooleanField(initial=True)
      #add the account owner
      
      def __str__(self):
          if(account_type == 'b')
              return self.number
          else
              return self.currency
  
new_contents: from django.db import models
  import datetime
  
  
  class Currency(models.Model):
      name = models.CharField(max_length=25)
      contraction = models.CarField(max_length=5)
      def __str__(self):
          return self.name
  
  
  class Account(models.Model):
      DEFAULT_CURRENCY_ID = 1 # pounds ?
      BANK = 'b'
      CASH = 'c'
      TYPE_CHOICES = (
          (BANK, 'Bank'),
          (CASH, 'Cash'),
      )
      account_type = models.CharField(max_length=5, choices=TYPE_CHOICES, default=CASH)
      bank_name = models.CharField(max_length=25, blank=True)
      number = models.CharField(max_length=140, blank=True)
      balance = models.DecimalField(decimal_places=10, max_digits=19, default=0)
      currency = models.ForeignKey(Currency, default=DEFAULT_CURRENCY_ID)
      active = models.BooleanField(initial=True)
      #add the account owner
      
      def __str__(self):
          if account_type == 'b'
              return self.number
          else
              return self.currency 
  
  
  class Transfer(models.Model):
      from_account =  models.ForeignKey(Account)
      to_account = models.ForeignKey(Account)
      amount = models.DecimalField(decimal_places=10, max_digits=19)
      exchange_rate = models.DecimalField(decimal_places=10, max_digits=19)
      date = models.DateTimeField(default=datetime.now())
  
       def __str__(self):
           return self.amount
  
subject: Create the transfer model of accounts