def __init__(self, type_, blob, comment=None):
self.key_type = type_<EOL>self.key_blob = blob<EOL>self.comment = comment<EOL>
Create a new public blob of given type and contents.

:param str type_: Type indicator, eg ``ssh-rsa``.
:param blob: The blob bytes themselves.
:param str comment: A comment, if one was given (e.g. file-based.)