input: Write a python function to process a payment and return the transaction count.
  assert process_payment_and_count(100, '12345', 'USD') == 1
  assert process_payment_and_count(200, '67890', 'EUR') == 2
  assert process_payment_and_count(150, '11223', 'GBP') == 3
output: def process_payment_and_count(amount, account_number, currency):
      if not hasattr(process_payment_and_count, "transaction_count"):
          process_payment_and_count.transaction_count = 0
      process_payment_and_count.transaction_count += 1
      # Here you would add the actual payment processing logic
      return process_payment_and_count.transaction_count