def METHOD_NAME():
    items1 = [
        {"id": {"S": "n1"}, "attr1": {"N": "1"}},
        {"id": {"S": "n2"}},
        {"id": {"S": "n3"}},
    ]
    key_schema1 = [{"AttributeName": "id", "KeyType": "HASH"}]
    items2 = [
        {"id": {"S": "id1"}, "num": {"N": "1"}},
        {"id": {"S": "id2"}, "num": {"N": "2"}},
        {"id": {"S": "id3"}, "num": {"N": "2"}},
    ]
    key_schema2 = [
        {"AttributeName": "id", "KeyType": "HASH"},
        {"AttributeName": "num", "KeyType": "RANGE"},
    ]
    samples = ((items1, key_schema1), (items2, key_schema2))
    for items, key_schema in samples:
        item_set = ItemSet(items, key_schema=key_schema)
        for item in items:
            assert item_set.find_item(item) == item
        for item in items:
            assert not item_set.find_item({**item, "id": {"S": item["id"]["S"] + "-new"}})