I little question about require_once

[Mauro_dev]

Hi, 

I am developing a payment gateway that is used in my country, which works with SOAP / WSDL, to integrate the API that they provide me I need to integrate PHP libraries, my question is, you can directly integrate these libraries in the function "mygatewaymethod_link" using "require_once" or "include"? Or does it require another process to integrate these libraries and use them? Try to integrate directly but I throw an error when trying to pay.

 

I attach an error image when I integrate it with require_once.

Regards