Here is how to download a youtube video with pytube in Python.

from pytube import YouTube

# URL of the video to download
video_url = 'https://www.youtube.com/watch?v=yQEQmRUyUzI' 

# Create a YouTube object
yt = YouTube(video_url)

# Get the highest resolution stream
stream = yt.streams.get_highest_resolution()

# Download the video
stream.download('output.mp4') 

Replace 'https://www.youtube.com/watch?v=yQEQmRUyUzI' with the URL of the video you want to download.

This code snippet downloads the highest-resolution version of the video. If you want to download a specific resolution or format, you can choose a different stream accordingly. For example, you can use yt.streams.get_by_resolution('720p') to download a video with a resolution of 720p.