WeChat.Material.upload_video

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

upload_video(client, media_id, title, description)

Specs

upload_video(WeChat.client(), media_id(), title(), description()) ::
  WeChat.response()

获取批量推送类型为 mpvideo 时要求的 media_id - 官方文档

media_id 需通过 [素材管理] -> [新增素材] 来得到