tzinfo.py 文件源码

def utcoffset(self, dt, is_dst=None):
        '''See datetime.tzinfo.utcoffset

        The is_dst parameter may be used to remove ambiguity during DST
        transitions.

        >>> from pytz import timezone
        >>> tz = timezone('America/St_Johns')
        >>> ambiguous = datetime(2009, 10, 31, 23, 30)

        >>> tz.utcoffset(ambiguous, is_dst=False)
        datetime.timedelta(-1, 73800)

        >>> tz.utcoffset(ambiguous, is_dst=True)
        datetime.timedelta(-1, 77400)

        >>> try:
        ...     tz.utcoffset(ambiguous)
        ... except AmbiguousTimeError:
        ...     print('Ambiguous')
        Ambiguous

        '''
        if dt is None:
            return None
        elif dt.tzinfo is not self:
            dt = self.localize(dt, is_dst)
            return dt.tzinfo._utcoffset
        else:
            return self._utcoffset