You need to Download pytube and moviepy for this code.
To install both of these libraries, you can use the following codes in your terminal.
pip install pytube
pip install moviepy
To run the file, open your terminal and type "python /PATH.../YouTube_Downloader.py". This will initiate the program and allow you to download YouTube videos.
Have fun (:
Small legal disclaimer.
You are allowed to download video of youtube for your own private use but you are not allowed to publish them in any way.