Configure SSO to a Salesforce IdP Sandbox Org

global class B2CRegistrationWrapper implements Auth.RegistrationHandler {
         /**
         * Instantiates the standard B2C Commerce handler to delegate the logic.
         */
         private Auth.B2CCommerceCloudRegistrationHandler getStandardHandler() {
         return new Auth.B2CCommerceCloudRegistrationHandler();
         }
         global User createUser(Id portalId, Auth.UserData data) {
         // You can add custom pre-processing logic here
         // Delegate to the standard handler
         return getStandardHandler().createUser(data);
         }
         global void updateUser(Id userId, Id portalId, Auth.UserData data) {
         // You can add custom logging or attribute mapping here
         // Delegate to the standard handler
         getStandardHandler().updateUser(userId, data);
         }
       }