将固定格式的字符串转换成对应的时间戳到秒级别

    - 使用:

    >>> str2unixtime('2016-01-01 01:01:01')
    1451581261

    :param ts:
    :type ts:
    :param fmt:
    :type fmt:
    :return:
    :rtype:

def str2unixtime(ts, fmt='%Y-%m-%d %H:%M:%S'):
    """
        将固定格式的字符串转换成对应的时间戳到秒级别

    - 使用:

    >>> str2unixtime('2016-01-01 01:01:01')
    1451581261

    :param ts:
    :type ts:
    :param fmt:
    :type fmt:
    :return:
    :rtype:
    """
    t = time.strptime(ts, fmt)
    return int(time.mktime(t))