def pair_sums(total, least):
    """Find all pairs which add up to the provided sum.

    Arguments:
        total (int): Number to which returned pairs must sum.
        least (int): The smallest integer which may be part of a returned pair.

    Returns:
        set of tuples: Containing pairs of integers adding up to the given sum.
    """
    pairs = set()
    for i in range(least, total - least):
        pair = [i, total - i]
        pair.sort()

        pairs |= set([tuple(pair)])

    return pairs