def _display_interval(i):
    """Convert a time interval into a human-readable string.

    :param i: The interval to convert, in seconds.
    """
    sigils = ['d', 'h', 'm', 's']
    factors = [24 * 60 * 60, 60 * 60, 60, 1]
    remain = int(i)
    result = ''
    for fac, sig in zip(factors, sigils):
        if remain < fac:
            continue
        result += '{}{}'.format(remain // fac, sig)
        remain = remain % fac
    return result
