WeChat.CardDistributing.set_test_whitelist

You're seeing just the function set_test_whitelist, go back to WeChat.CardDistributing module for more information.
Link to this function

set_test_whitelist(client, list)

Specs

set_test_whitelist(WeChat.client(),
  openid: WeChat.openid_list(),
  username: WeChat.User.username_list()
) :: WeChat.response()

设置测试白名单 - 官方文档

Link to this function

set_test_whitelist(client, openid_list, username_list)

Specs

设置测试白名单 - 官方文档