Ok, I see one problem with this method.
When one will it a second time with another `MagentoSoapClientParameters` instance, it will return the result of the first time the method was called, even if it was with a totally unrelated `MagentoSoapClientParameters` instance.

Instead, I'd rather store the result (as a cache) in the current class and use a precise enough key (can be the spl_object_hash or any unique attribute of the object) and returns it when it was previously checked.