I'm writing a new custom tap using the Meltano SDK "RESTStream" class. I want to pick a replication_key (last updated timestamp), but in my input that I received from the remote API, the timestamp is a nested field. Is there an easy way to use a nested field as the replication_key? example data:

"results": [
 {
   "last_updated": {
     "value": "2022-03-01 00:00:10",
     "display_value": "2022-03-01 00:00:10"
   },
   "name": {
     "value": "John Doe",
     "display_value": "John Doe"
   }
 },
 {
   .. next record
 }
]