def check_textbound_overlap(anns):
    """
    Checks for overlap between the given TextBoundAnnotations.
    Returns a list of pairs of overlapping annotations.
    """
    overlapping = []
    for anno1 in anns:
        for anno2 in anns:
            if anno1 is anno2:
                continue
            if anno2.first_start() < anno1.last_end() and anno2.last_end(
                ) > anno1.first_start():
                overlapping.append((anno1, anno2))
    return overlapping
