def reply_to(self) -> Optional[Sequence[AddressHeader]]:
        """The ``Reply-To`` header."""
        try:
            return cast(Sequence[AddressHeader], self[b'reply-to'])
        except KeyError:
            return None
def reply_to ( self ) -> Optional [ Sequence [ AddressHeader ] ] : try : return cast ( Sequence [ AddressHeader ] , self [ b'reply-to' ] ) except KeyError : return None
The ``Reply-To`` header.