':param subject: The subject its all about as a <Subject> instance
:param destination: The IdP endpoint to send the request to
:param authn_context: list of <RequestedAuthnContext> instances
:param session_index: a specified session index
:param message_id: Message identifier
:param consent: If the principal gave her consent to this request
:param extensions: Possible request extensions
:param sign: Whether the request should be signed or not.
:return:'

def create_authn_query(self, subject, destination=None, authn_context=None, session_index='', message_id=0, consent=None, extensions=None, sign=False, nsprefix=None):

    return self._message(AuthnQuery, destination, message_id, consent, extensions, sign, subject=subject, session_index=session_index, requested_authn_context=authn_context, nsprefix=nsprefix)
