How to get the last item in an iterable

lastiter.py

import typing as t

T_iter = t.TypeVar("T_iter")

def which_is_last(data: t.Iterable[T_iter]) -> t.Iterator[t.Tuple[T_iter, bool]]:
    """Given an iterable, return an iterable of value, bool pairs
    where the bool is True iff this is the last item."""
    last_found: T_iter
    has_value = False

    for item in data:
        if has_value:
            yield last_found, False
        last_found = item
        has_value = True
    else:
        if has_value:
            yield last_found, True

if __name__ == "__main__":
    for item, last in which_is_last([1, 2, 3]):
        print(item, last)
    
    for item, last in which_is_last(a for a in range(5)):
        print(item, last)
    
    for item, last in which_is_last([]):
        print(item, last)