text: class TRetriever:
      def __init__(self, client, accountnumber):
          self.client = client
          self.accountnumber = accountnumber
  
      def get_hbci_transactions(self, start_date, end_date):
          accounts = self.client.get_sepa_accounts()
  
          account = self.__find_matching_account(accounts, self.accountnumber)
  
          return self.client.get_transactions(account, start_date, end_date)
  
      def __find_matching_account(self, accounts, accountnumber):
          for account in accounts:
              if account.accountnumber == accountnumber:
                  return account
          raise Exception("Could not find a matching account for account number '{missing_account}'. Possible accounts: {accounts}"
                          .format(missing_account=accountnumber, accounts=accounts))
  