PatchDocumentsResponse does not expose _oldRev

[DiscoPYF]

PatchDocumentsResponse is the model representing one object from the response when updating multiple document. In the response returned by ArangoDB, the key of the old document is provided in _oldRev. However PatchDocumentsResponse doesn't contain an equivalent for that property.

Example of response:

[
    {
        "_id": "MYTESTCLX/61264991",
        "_key": "61264991",
        "_rev": "_ax7nWEW---",
        "_oldRev": "_ax7j2pq--_"
    },
    {
        "_id": "MYTESTCLX/61264916",
        "_key": "61264916",
        "_rev": "_ax7nWEW--A",
        "_oldRev": "_ax7jvi2--_"
    }
]