def __init__(self, msg=None, data=None):
pass<EOL>
Create a new instance of this public key type.  If C{msg} is given,
the key's public part(s) will be filled in from the message.  If
C{data} is given, the key's public part(s) will be filled in from
the string.

@param msg: an optional SSH L{Message} containing a public key of this
type.
@type msg: L{Message}
@param data: an optional string containing a public key of this type
@type data: str

@raise SSHException: if a key cannot be created from the C{data} or
C{msg} given, or no key was passed in.