Like find-first-key, but searches the sequence from end to start.
sealed
| seq | An instance of <vector>. |
| pred? | An instance of <function> that returns #t for a matching condition. |
| start: | An instance of <integer> from which element to start the search. Defaults to 0. |
| end: | An instance of <integer> at which to end the search. Defaults to the size of seq. |
| failure: | An instance of <object>. Returned if no match found. Defaults to #f. |
| key-or-failure | An instance of <integer> or the failure value. |