'Deal with a LogoutRequest
:param xmlstr: The response as a xml string
:param binding: What type of binding this message came through.
:return: None if the reply doesn\'t contain a valid SAML LogoutResponse,
otherwise the reponse if the logout was successful and None if it
was not.'

def parse_logout_request(self, xmlstr, binding=BINDING_SOAP):

    return self._parse_request(xmlstr, saml_request.LogoutRequest, 'single_logout_service', binding)
