def compute_CI(allele_size, repeat_unit_length):
    """Compute a pseudo "confidence interval" based on the criteria using for mendelian violation tests in the
    STRling pre-print - where a genotype was considered not to be a mendelian violation if it was within
    25% or 10bp of the expected genotype.

    Args:
        allele_size (int): The number of repeats.
        repeat_unit_length (str): Length of the repeat unit in base pairs.

    Returns:
         str: "{lower}-{upper}" representing the lower/upper bound in numbers of repeats.
    """
    max_repeats_distance = 10.0  # based on this utility script in the STRling repo: https://github.com/laurelhiatt/strling-MV/blob/main/denovo.py#L170
    fraction = 0.25
    lower = int(round(min(allele_size - max_repeats_distance, (1-fraction) * allele_size)))
    upper = int(round(max(allele_size + max_repeats_distance, (1+fraction) * allele_size)))

    lower = max(0, lower)

    return f"{lower}-{upper}"