'Get html for a form to submit this request to the IDP.
@param form_tag_attrs: Dictionary of attributes to be added to
the form tag. \'accept-charset\' and \'enctype\' have defaults
that can be overridden. If a value is supplied for
\'action\' or \'method\', it will be replaced.
@type form_tag_attrs: {unicode: unicode}'

def formMarkup(self, realm, return_to=None, immediate=False, form_tag_attrs=None):

    message = self.getMessage(realm, return_to, immediate)
    return message.toFormMarkup(self.endpoint.server_url, form_tag_attrs)
