Convert a number of seconds into readable days, hours, and minutes

def readable_time_delta(seconds):
    """
    Convert a number of seconds into readable days, hours, and minutes
    """
    days = seconds // 86400
    seconds -= days * 86400
    hours = seconds // 3600
    seconds -= hours * 3600
    minutes = seconds // 60

    m_suffix = 's' if minutes != 1 else ''
    h_suffix = 's' if hours != 1 else ''
    d_suffix = 's' if days != 1 else ''

    retval = u'{0} minute{1}'.format(minutes, m_suffix)

    if hours != 0:
        retval = u'{0} hour{1} and {2}'.format(hours, h_suffix, retval)

    if days != 0:
        retval = u'{0} day{1}, {2}'.format(days, d_suffix, retval)

    return retval