Can you clarify the complexity of append(contentsOf:)?

[rzulkoski]

In regards to complexity, the documentation for IdentifiedArray.append(contentsOf:) states the following:

The operation is expected to perform amortized O(1) copy, hash, and compare operations on the Element type, if it implements high-quality hashing.

But wouldn't the overall complexity of this operation scale with the number of elements being appended, or even the number of elements in the original identified array?