Syspay Merchant SDK
| Syspay_Merchant_Entity_ReturnedEntityInterface | Entities that are built based on an API call response must implement this | 
| Syspay_Merchant_EMSException | Exception thrown when an EMS callback cannot be interpreted | 
| Syspay_Merchant_RedirectException | Exception thrown when the results given in a redirection cannot be validated | 
| Syspay_Merchant_RequestException | Exception thrown when an API request fails | 
| Syspay_Merchant_UnexpectedResponseException | Exception thrown when the response received from the API could not be parsed |