For now, this isn't used for much: it's a record of the recent refundable purchases that the user has made. In the future, it could be used for providing refunds/buyback via the API. Wouldn't that be fun?
Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
) → String
Returns a string representation of this object.
dynamic other) → bool
The equality operator.