def pretty_duration(seconds):
    """ Returns a user-friendly representation of the provided duration in seconds.
    For example: 62.8 => "1m2.8s", or 129837.8 => "2d12h4m57.8s"
    """
    if seconds is None:
        return ''
    ret = ''
    if seconds >= 86400:
        ret += '{:.0f}d'.format(int(seconds / 86400))
        seconds = seconds % 86400
    if seconds >= 3600:
        ret += '{:.0f}h'.format(int(seconds / 3600))
        seconds = seconds % 3600
    if seconds >= 60:
        ret += '{:.0f}m'.format(int(seconds / 60))
        seconds = seconds % 60
    if seconds > 0:
        ret += '{:.1f}s'.format(seconds)
    return ret