# Withdraw amount from each of accounts in list_of_accounts
def batch_withdraw(list_of_accounts, amount):
   for acct in list_of_accounts:
      acct.withdraw(amount)

b, c, s = BankAccount(1000), CheckingAccount(2000), SavingsAccount(3000)
batch_withdraw([b,c,s]) # <-- Will use BankAccount.withdraw(),
                              # then CheckingAccount.withdraw(),
                              # then SavingsAccount.withdraw()

• batch_withdraw() को यह जाँचने की ज़रूरत नहीं कि किस ऑब्जेक्ट पर कौन सा withdraw() कॉल करना है