batched_chunks over lazy iterables

"""Split any iterable into fixed-size lists without materialising it first."""
from collections.abc import Iterable, Iterator
from itertools import islice
from typing import TypeVar

T = TypeVar("T")


def batched_chunks(iterable: Iterable[T], size: int) -> Iterator[list[T]]:
    """Yield lists of at most size items; the final batch may be shorter."""
    if size < 1:
        raise ValueError("size must be at least 1")
    source = iter(iterable)
    while batch := list(islice(source, size)):
        yield batch


if __name__ == "__main__":
    print(list(batched_chunks(range(7), 3)))  # [[0, 1, 2], [3, 4, 5], [6]]
    print(list(batched_chunks("abcde", 2)))  # [['a', 'b'], ['c', 'd'], ['e']]