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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def update_config(self, svc_config, **rt_configs):
 """ Update the service's configuration. @param svc_config: Dictionary with service configuration to update. @param rt_configs: Dict of role type configurations to update. @return: 2-tuple (service config dictionary, role type configurations) """

    path = self._path() + '/config'

    if svc_config:
      data = config_to_api_list(svc_config)
    else:
      data = { }
    if rt_configs:
      rt_list = [ ]
      for rt, cfg in rt_configs.iteritems():
        rt_data = config_to_api_list(cfg)
        rt_data['roleType'] = rt
        rt_list.append(rt_data)
      data[ROLETYPES_CFG_KEY] = rt_list

    resp = self._get_resource_root().put(path, data = json.dumps(data))
    return self._parse_svc_config(resp)