Use this endpoint to create or update a list entry for a given parent record. If an entry with the specified parent record is found, that entry will be updated. If no such entry is found, a new entry will be created instead. If there are multiple entries with the same parent record, this endpoint with return the "MULTIPLE_MATCH_RESULTS" error. When writing to multi-select attributes, all values will be either created or deleted as necessary to match the list of values supplied in the request body.