Generate previews of the invoices that will be created from the provided contract.
Contract to preview invoice creation for
Indexes of the invoices to generate from each recurrence (e.g. [0, 1, 2] for the first three invoices). Note that contracts with multiple recurrences will generate more preview invoices, and invalid invoice indexes will be ignored silently. For example, [0, 1, 2] on a contract with 2 recurrences will generate at most 6 invoices, and potentially fewer if some of indexes are out of bounds for a recurrence.