@classmethod<EOL><INDENT>def from_message(cls, message):<DEDENT>
type_ = message.get_text()<EOL>return cls(type_=type_, blob=message.asbytes())<EOL>
Create a public blob from a network `.Message`.

Specifically, a cert-bearing pubkey auth packet, because by definition
OpenSSH-style certificates 'are' their own network representation."