def METHOD_NAME():
    class _BookResource(resources.ModelResource):
        def for_delete(self, row, instance):
            return True
        class Meta:
            model = Book
            fields = ("id", "name", "author_email", "price")
            use_bulk = True
            batch_size = 1000
            skip_diff = True
            instance_loader_class = CachedInstanceLoader
    print("\ndo_delete()")
    # clearing down existing objects
    books = Book.objects.all()
    books._raw_delete(books.db)
    rows = [("", "Some new book", "email@example.com", "10.25")] * NUM_ROWS
    books = [Book(name=r[1], author_email=r[2], price=r[3]) for r in rows]
    # deletes - there must be existing rows in the DB...
    # i.e. so they can be deleted
    Book.objects.bulk_create(books)
    assert NUM_ROWS == Book.objects.count()
    all_books = Book.objects.all()
    rows = [(b.id, b.name, b.author_email, b.price) for b in all_books]
    dataset = tablib.Dataset(*rows, headers=["id", "name", "author_email", "price"])
    book_resource = _BookResource()
    do_import_duration(book_resource, dataset)
    assert 0 == Book.objects.count()
    # recreate rows which have just been deleted
    Book.objects.bulk_create(books)
    assert NUM_ROWS == Book.objects.count()
    all_books = Book.objects.all()
    rows = [(b.id, b.name, b.author_email, b.price) for b in all_books]
    dataset = tablib.Dataset(*rows, headers=["id", "name", "author_email", "price"])
    do_import_mem(book_resource, dataset)
    assert 0 == Book.objects.count()