def verify_signature(self):
if self.get_contact_key:<EOL><INDENT>sender_key = self.get_contact_key(self.sender_handle)<EOL><DEDENT>else:<EOL><INDENT>sender_key = fetch_public_key(self.sender_handle)<EOL><DEDENT>if not sender_key:<EOL><INDENT>raise NoSenderKeyFoundError("<STR_LIT>")<EOL><DEDENT>MagicEnvelope(doc=self.doc, public_key=sender_key, verify=True)<EOL>
Verify the signed XML elements to have confidence that the claimed
author did actually generate this message.