Python library: pytube get_highest_resolution()

Could someone help me? I have a code using Python and the pytube library to donwloand some YouTube videos. But I have a doubt with the video resolution. I use the get_highest_resolution to set the video quality when I download it. But for example, I chose a video which the highest resolution is 1080p, but even I am using the command(get_highest_resolution()), the video is gonna get download with 720p as the resolution, and it is still with a lower quality than the original video on YouTube. Who knows why it is happ开发者_如何学Cening?

First of all, I thought that it could be a library limitation. I tried to use some kind of different type of command as well, but without success.

This may be the reason... https://pytube.io/en/latest/user/streams.html#downloading-streams

literal quotation from the top url: "The legacy streams that contain the audio and video in a single file (referred to as “progressive download”) are still available, but only for resolutions 720p and below."