Create a new or update an existing shelf instance record.
| shelfID | Shelf Instance ID, supply to edit an existing shelf instance; otherwise, do not include when adding a new shelf instance |
| instID | Institution ID of the holding institute |
| shelfNum | Shelf Number, assigned by the holding institute |
| formerGA | if this shelf instance was given a Gregory Aland number previously, which is now deprecated. |
| contentOverview | Content Overview, e.g., eapr |
| leavesDesc | Leaves Description, e.g., 12 fragments. |
| leavesCount | Leaves Count, e.g., 12 |
| origYearDesc | Origin Year Description, e.g., III |