item_upsert never updates

[aappling-usgs]

I can't find a way to call item_upsert such that it updates rather than creates a new item.

After logging in:

test_item_1 <- item_upsert(title="books1") 
test_item_2 <- item_upsert(title="books1") 
test_item_1$id == test_item_2$id
## [1] FALSE
test_item_3 <- item_upsert(title="books2")
test_item_4 <- item_upsert(title="books2", info=list(contacts = list(list(name = "Suzy"))))
test_item_3$id == test_item_4$id
## [1] FALSE

I had expected the tests to yield TRUE - i.e., item_upsert should update rather than create an existing item if the titles match. The two calls to item_upsert in the Examples section of the help document also produce two distinct items, despite the claim that the second call "updates this time".