SLAPI uses calls to our "verbs" as a way to simplify interactions with marketplaces and 3rd-party resources in a format and style consistent with the rest of SLAPI. In most cases, we are simply exposing the same data that would be used in call directly to the merchant. However, by using SLAPI authentication, naming conventions, and style, it saves the developer from interacting with these marketplaces directly and having to perform a lot of tedious work in maintaining other libraries, converting varibale names, etc.
API calls to the verbs do not modify any state
Our verb calls are all proceeded with the prefix of "calc"