tz.py 文件源码

def get(self, tzid=None):
        if tzid is None:
            keys = list(self._vtz.keys())
            if len(keys) == 0:
                raise ValueError("no timezones defined")
            elif len(keys) > 1:
                raise ValueError("more than one timezone available")
            tzid = keys[0]
        return self._vtz.get(tzid)