WeChat.User.batch_get_user_info

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

batch_get_user_info(client, user_list)

Specs

batch_get_user_info(WeChat.client(), [
  %{:openid => WeChat.openid(), optional(:lang) => lang()}
]) :: WeChat.response()

批量获取用户基本信息 - 官方文档