According to my knowledge you are telling how to retrieve a text from the file. for example primes.txt , but I don't have that text in my folder.
While teaching this you need to educate us to save the text files before rather than just retrieve the text file directly. kindly check you video.
if I am wrong kindly suggest me
Python-3.4.3 Loading-Data-From-Files 04-05 min 10-20 sec
You can get the relevant files from the Code file section on this page
you can use this for creating a text file
hello how are you
welcome to python programming
it will create file in your current directory
you can load that file using %load text1.txt