An enumerated type for the values that represent the eBay seller's trust level. 
Valid Values: TOP_RATED, ABOVE_STANDARD, or an empty value. 
An empty value indicates a return of anything other than TOP_RATED or ABOVE_STANDARD.
Code so that your app gracefully handles any future changes to this list.
Types that use SellerTrustLevelEnum
Calls that use SellerTrustLevelEnum
GET
Enumerations
TOP_RATED
 Indicates the seller is an eBay top rated seller (the highest standing).
ABOVE_STANDARD
 Indicates the seller is above the eBay standard.