tz.py 文件源码

def __init__(self, s):
        global parser
        if not parser:
            from dateutil import parser
        self._s = s

        res = parser._parsetz(s)
        if res is None:
            raise ValueError("unknown string format")

        # Here we break the compatibility with the TZ variable handling.
        # GMT-3 actually *means* the timezone -3.
        if res.stdabbr in ("GMT", "UTC"):
            res.stdoffset *= -1

        # We must initialize it first, since _delta() needs
        # _std_offset and _dst_offset set. Use False in start/end
        # to avoid building it two times.
        tzrange.__init__(self, res.stdabbr, res.stdoffset,
                         res.dstabbr, res.dstoffset,
                         start=False, end=False)

        if not res.dstabbr:
            self._start_delta = None
            self._end_delta = None
        else:
            self._start_delta = self._delta(res.start)
            if self._start_delta:
                self._end_delta = self._delta(res.end, isend=1)