def METHOD_NAME(intra, seen, test_merged_otu):
    seen_sequence_ids = set()
    if intra:
        test_merged_otu["isolates"][0]["sequences"].append(
            test_merged_otu["isolates"][0]["sequences"][0]
        )
    if seen:
        seen_sequence_ids.add("abcd1234")
    duplicate_sequence_ids = set()
    detect_duplicate_sequence_ids(
        test_merged_otu, duplicate_sequence_ids, seen_sequence_ids
    )
    if intra or seen:
        assert duplicate_sequence_ids == {"abcd1234"}
    else:
        assert duplicate_sequence_ids == set()
    assert seen_sequence_ids == {"abcd1234"}