section ATM
  description   Messages mainly used for interaction with the ATM.
  message validate-card A card need to be validated
  message card-valid The card is valid
  message card-invalid The card is invalid, e.g. cannot be read
  message card-fraudulent The card is marked as fraudulent and will be confiscated
  message authorize The customer has given its pin/password to authorize himself
  message auth-valid The authorization is valid
  message auth-invalid The authorization is invalid
  message display-balance The customer wants to see the balance.
  message balance-displayed The ATM shows the balance
  message withdraw-cash The customer wants to withdraw cash
  message cash-issued The cash has been issued to the customer
  message deposit-cash The customer wants to deposit cash
  message not-enough-cash The customer does not have enough cash for the withdrawal
  message deposit-successful The deposit was successfully handled
  message deposit-failed The deposit failed for some reason
  message insuf-balance The customer does not have enough balance to withdraw
  message insufficient-cash The ATM knows it does not have enough cash
  message confirm-amount The counted cash needs to be confirmed by the customer
  message amount-confirmed The customer agrees with the amount counted
  message withdraw-successful The withdraw was accepted.
  message abort-deposit The customer aborts the deposit
  message deposit-aborted The deposit is aborted and the money is returned
  message out-of-order The ATM is now out of order
  protocol Human Used to describe human readable messages.