':param respdict:
:param idp_entity_id:
:return:'

def ecp_conversation(self, respdict, idp_entity_id=None):

    args = self.parse_sp_ecp_response(respdict)
    idp_response = self.phase2(idp_entity_id=idp_entity_id, **args)
    ht_args = self.use_soap(idp_response, args['rc_url'], [args['relay_state']])
    logger.debug(('[P3]    Post    to    SP:    %s' % ht_args['data']))
    ht_args['headers'].append(('Content-Type', 'application/vnd.paos+xml'))
    response = self.send(args['rc_url'], 'POST', **ht_args)
    if (response.status_code == 302):
        pass
    else:
        print response.error
        raise SAMLError(('Error    POSTing    package    to    SP:    %s' % response.error))
    logger.debug(('[P3]    SP    response:    %s' % response.text))
    self.done_ecp = True
    logger.debug('Done    ECP')
    return None
