To install pytube, run the following command in your terminal:
pip install pytube
In the code:
from pytube import YouTube
Then create the list of videos that would like to download as
Links = ['https://www.youtube.com/watch?v=DayfXQXyenQ']
for Video in Links:
yt = YouTube(Video)
B = yt.streams.get_by_itag(18)
The provided script would save the Youtube video in the current directory.
P.S. This is your responsibility to consider the Copy Right of the videos.