code: def unixtime2str(timestamp, fmt='%Y-%m-%d %H:%M:%S'):
      
      dt = None
      try:
          timestamp = time.localtime(timestamp)
          dt = time.strftime(fmt, timestamp)
      except Exception as err:
          print(err)
      return dt
docs: 将 ``秒级别的时间戳`` 转换成字符串
  
      .. warning:
          时间戳是以 ``秒`` 为单位的
  
      :param timestamp: unix timestamp
      :type timestamp: int
      :param fmt: show format
      :type fmt: str
      :return:
      :rtype: str