if self.expiration.tzinfo is not None and self.expiration.tzinfo.utcoffset(self.expiration) is not None:
# TZ aware. Make sure it is UTC
self.expiration = self.expiration.astimezone(tz.tzutc())
if self.expiration.tzinfo is not None and self.expiration.tzinfo.utcoffset(self.expiration) is not None:
# TZ aware. Make sure it is UTC
self.expiration = self.expiration.astimezone(tz.tzutc())