code: def to_utctimestamp(a_datetime):
      
      if a_datetime.tzinfo is None:
          delta = a_datetime - datetime(1970, 1, 1)
      else:
          delta = a_datetime - datetime(1970, 1, 1, tzinfo=utc)
      return delta.total_seconds()
docs: Calculate number of seconds from UTC 1970-01-01 00:00:00.
  
      When:
  
      - dt doesn't have tzinfo: assume it's a utc time.
      - dt has tzinfo: use tzinfo.
  
      WARNING, if your datetime object doens't have ``tzinfo``, make sure
      it's a UTC time, but **NOT a LOCAL TIME**.
  
      **中文文档**
  
      计算时间戳, 若:
  
      - 不带tzinfo: 则默认为是UTC time。
      - 带tzinfo: 则使用tzinfo。