_common.py 文件源码

def _isdst(self, dt):
        if not self.hasdst:
            return False
        elif dt is None:
            return None

        transitions = self.transitions(dt.year)

        if transitions is None:
            return False

        dt = dt.replace(tzinfo=None)

        isdst = self._naive_isdst(dt, transitions)

        # Handle ambiguous dates
        if not isdst and self.is_ambiguous(dt):
            return not self._fold(dt)
        else:
            return isdst