def _chunk(self, size):
        """
        Chunk the underlying collection.

        :param size: The chunk size
        :type size: int

        :rtype: Collection
        """
        items = self.items

        return [items[i:i + size] for i in range(0, len(items), size)]
Chunk the underlying collection.

        :param size: The chunk size
        :type size: int

        :rtype: Collection